GIANT CLUSTERFUCK OF A COMMIT

OK, this is epic.  I was basically just trying to a) support Clang and
b) add more test coverage.  _THREE MONTHS_ and a few hundred CI runs
later, this is what I came up with.  I don't know how it ended up being
what it is, but here we go.

Some highlights of the changes:

1) CI builds has been moved to GitHub Actions,
2) the entire notion of a toolchain has been reworked; it now supports
Clang on all platforms.

* .github: this directory contains the GitHub Actions workflow
scripts/actions.  In the process, I created like 6 external GitHub
actions, but it's still pretty massive.  An upside is that it covers
much more platform/toolchain combinations _and_ check a lot of the
expected post-conditions.  TODO: .ci/Makefile is obsolete now, as well
as .travis.yml and .appveyor.yml.

* common.cmake: added Clang support.  In the process, a great deal has
been learned about how CMake works; in particular, static runtime
support has been reworked to be more robust.

* project: the entire notion of a "toolchain" has been reworked.
Instead of a measly --mingw parameter, there's now a separate --toolset
parameter, which allows you to choose between GCC, Clang, MSVC, etc.
Both Boost and CMake build scripts were enhanced greatly to support
Clang and other toolchains in a more robust way.

16 files changed, 1348 insertions, 0 deletions

diff --git a/.github/actions/build-boost/action.yml b/.github/actions/build-boost/action.yml
new file mode 100644
index 0000000..1f8a46c
--- /dev/null
+++ b/.github/actions/build-boost/action.yml
@@ -0,0 +1,53 @@
+name: Build Boost
+description: Build Boost
+inputs:
+  boost-dir:
+    description: Boost directory
+    required: false
+  toolset:
+    description: Toolset to use
+    required: false
+    default: auto
+  libraries:
+    description: Libraries to build
+    required: false
+  platform:
+    description: Target platform
+    required: false
+    default: x64
+  configuration:
+    description: Configuration to build
+    required: false
+    default: Debug
+runs:
+  using: composite
+  steps:
+    - run: |
+        $python = 'python'
+
+        $boost_dir = '${{ inputs.boost-dir }}'
+        if (-not $boost_dir) {
+            $boost_dir = $env:BOOST_DIR
+        }
+
+        $libraries = '${{ inputs.libraries }}'
+        $libraries = $libraries.Split(' ') | %{ "--with-$_" }
+        if (-not $libraries) {
+            Remove-Variable libraries
+        }
+
+        if ($env:CI_HOST_CYGWIN) {
+            $python = 'python3'
+            $boost_dir = cygpath.exe -ua $boost_dir
+        }
+
+        & $python `
+            -m project.boost.build `
+            --verbose `
+            --toolset '${{ inputs.toolset }}' `
+            --platform '${{ inputs.platform }}' `
+            --configuration '${{ inputs.configuration }}' `
+            -- `
+            $boost_dir `
+            $libraries
+      shell: pwsh
diff --git a/.github/actions/build-example/action.yml b/.github/actions/build-example/action.yml
new file mode 100644
index 0000000..97cc627
--- /dev/null
+++ b/.github/actions/build-example/action.yml
@@ -0,0 +1,69 @@
+name: Build example project
+description: Build example project
+inputs:
+  src-dir:
+    description: Project directory
+    required: true
+  boost-dir:
+    description: Boost directory
+    required: false
+  toolset:
+    description: Toolset to use
+    required: false
+    default: auto
+  platform:
+    description: Target platform
+    required: false
+    default: x64
+  configuration:
+    description: Configuration to build
+    required: false
+    default: Debug
+outputs:
+  install-dir:
+    description: Installation directory
+    value: '${{ steps.install-dir.outputs.path }}'
+runs:
+  using: composite
+  steps:
+    - id: install-dir
+      run: |
+        $src_dir = Resolve-Path '${{ inputs.src-dir }}'
+        $project_name = Split-Path $src_dir -Leaf
+        $install_dir = Join-Path (Split-Path $env:GITHUB_WORKSPACE) "install_$project_name"
+        echo "::set-output name=path::$install_dir"
+      shell: pwsh
+    - run: |
+        $python = 'python'
+        $src_dir = '${{ inputs.src-dir }}'
+        $install_dir = '${{ steps.install-dir.outputs.path }}'
+        $boost_dir = '${{ inputs.boost-dir }}'
+
+        if ($env:CI_HOST_CYGWIN) {
+            $python = 'python3'
+            $src_dir = cygpath.exe -ua $src_dir
+            $install_dir = cygpath.exe -ua $install_dir
+            if ($boost_dir) {
+                $boost_dir = cygpath.exe -ua $boost_dir
+            }
+        }
+
+        $args = @(
+            '--install',
+            $install_dir,
+            '--platform',
+            '${{ inputs.platform }}',
+            '--configuration',
+            '${{ inputs.configuration }}',
+            '--toolset',
+            '${{ inputs.toolset }}'
+        )
+
+        if ($boost_dir) {
+            $args += '--boost',$boost_dir
+        }
+
+        $args += '--',$src_dir
+        $env:VERBOSE = 1
+        & $python -m project.cmake.build $args
+      shell: pwsh
diff --git a/.github/actions/check-arch/action.yml b/.github/actions/check-arch/action.yml
new file mode 100644
index 0000000..b85be4e
--- /dev/null
+++ b/.github/actions/check-arch/action.yml
@@ -0,0 +1,23 @@
+name: Verify architecture
+description: Verify target architecture
+inputs:
+  path:
+    description: Installation directory
+    required: true
+  expected:
+    description: Target platform
+    required: true
+runs:
+  using: composite
+  steps:
+    - run: |
+        $script_path = if ($env:CI_TARGET_PE) {
+            Join-Path $env:GITHUB_WORKSPACE '.ci' 'verify_arch.ps1'
+        } else {
+            Join-Path $env:GITHUB_WORKSPACE '.ci' 'verify_arch.sh'
+        }
+
+        $exe_path = (Join-Path '${{ inputs.path }}' 'bin' 'foo') + $env:CI_EXE_EXT
+
+        & $script_path $exe_path '${{ inputs.expected }}'
+      shell: pwsh
diff --git a/.github/actions/check-boost-bootstrapped/action.yml b/.github/actions/check-boost-bootstrapped/action.yml
new file mode 100644
index 0000000..73f44a9
--- /dev/null
+++ b/.github/actions/check-boost-bootstrapped/action.yml
@@ -0,0 +1,44 @@
+name: Check that Boost was bootstrapped
+description: Check that Boost was bootstrapped
+runs:
+  using: composite
+  steps:
+    - run: |
+        echo '----------------------------------------------------------------'
+        echo 'bootstrap.log'
+        echo '----------------------------------------------------------------'
+        $path = Join-Path $env:BOOST_DIR 'bootstrap.log'
+        cat $path
+      shell: pwsh
+    - run: |
+        echo ''
+        echo '----------------------------------------------------------------'
+        echo 'project-config.jam'
+        echo '----------------------------------------------------------------'
+        $path = Join-Path $env:BOOST_DIR 'project-config.jam'
+        if (Test-Path $path -Type Leaf) {
+            cat $path
+        }
+      shell: pwsh
+    - run: |
+        echo ''
+        echo '----------------------------------------------------------------'
+        echo 'Checking that b2 executable was built'
+        echo '----------------------------------------------------------------'
+        $name = 'b2'
+        $path = Join-Path $env:BOOST_DIR $name
+
+        $exists_plain = Test-Path $path -Type Leaf
+        $exists_exe = Test-Path "${path}.exe" -Type Leaf
+        $exists = if ($env:CI_HOST_CYGWIN) {
+            $exists_plain -or $exists_exe
+        } elseif ($env:CI_HOST_WINDOWS) {
+            $exists_exe
+        } else {
+            $exists_plain
+        }
+
+        if (-not $exists) {
+            throw "b2 executable wasn't found"
+        }
+      shell: pwsh
diff --git a/.github/actions/check-boost-libraries/action.yml b/.github/actions/check-boost-libraries/action.yml
new file mode 100644
index 0000000..88df016
--- /dev/null
+++ b/.github/actions/check-boost-libraries/action.yml
@@ -0,0 +1,77 @@
+name: Check that Boost libraries were built
+description: Check that Boost libraries were built
+inputs:
+  boost-dir:
+    description: Boost directory
+    required: false
+  libraries:
+    description: Libraries to check
+    required: true
+  platform:
+    description: Target platform
+    required: false
+    default: x64
+  configuration:
+    description: Configuration to check
+    required: false
+    default: Debug
+runs:
+  using: composite
+  steps:
+    - run: |
+        $boost_dir = '${{ inputs.boost-dir }}'
+        if (-not $boost_dir) {
+            $boost_dir = $env:BOOST_DIR
+        }
+
+        $libraries = '${{ inputs.libraries }}'
+        $libraries = $libraries.Split(' ')
+
+        $stagedir = Join-Path 'stage' '${{ inputs.platform }}' '${{ inputs.configuration }}'
+        $librarydir = Join-Path $boost_dir $stagedir 'lib'
+
+        function Get-FileStubs {
+            param(
+                [Parameter(Mandatory=$true)]
+                [string] $lib
+            )
+
+            if ($lib -eq 'test') {
+                "prg_exec_monitor","test_exec_monitor","unit_test_framework"
+            } else {
+                @($lib)
+            }
+        }
+
+        $files = @()
+        foreach ($lib in $libraries) {
+            $stubs = Get-FileStubs $lib
+            foreach ($stub in $stubs) {
+                $files += "${env:CI_LIB_PREFIX}boost_$stub${env:CI_LIB_EXT}"
+            }
+        }
+        $files = $files | Sort-Object
+
+        echo '----------------------------------------------------------------'
+        echo 'Expected files'
+        echo '----------------------------------------------------------------'
+        echo $files
+
+        echo ''
+        echo '----------------------------------------------------------------'
+        echo 'Actual files'
+        echo '----------------------------------------------------------------'
+        echo (Get-ChildItem $librarydir | Sort-Object Name).Name
+
+        $missing = @()
+
+        foreach ($file in $files) {
+            if (!(Test-Path (Join-Path $librarydir $file) -Type Leaf)) {
+                $missing += $file
+            }
+        }
+
+        if ($missing.Count -ne 0) {
+            throw "These libraries are missing: $($missing -join ', ')"
+        }
+      shell: pwsh
diff --git a/.github/actions/check-runtime-library/action.yml b/.github/actions/check-runtime-library/action.yml
new file mode 100644
index 0000000..3025334
--- /dev/null
+++ b/.github/actions/check-runtime-library/action.yml
@@ -0,0 +1,161 @@
+name: Verify runtime library linkage
+description: Verify runtime library linkage (static or shared)
+inputs:
+  path:
+    description: Installation directory
+    required: true
+runs:
+  using: composite
+  steps:
+    - run: |
+        New-Variable path -Value '${{ inputs.path }}' -Option Constant
+
+        function Parse-DllLine {
+            param(
+                [Parameter(Mandatory=$true)]
+                [string] $Line
+            )
+
+            if ($Line -match '^\s*DLL Name:\s*(?<dll>\S+)\s*$') {
+                $Matches.dll
+            } else {
+                throw "Line doesn't match the pattern: $Line"
+            }
+        }
+
+        function Parse-PeHeaders {
+            param(
+                [Parameter(ValueFromPipeline)]
+                [string[]] $Output
+            )
+
+            process {
+                $Output | Select-String 'DLL Name:' -SimpleMatch -CaseSensitive | %{
+                    Parse-DllLine $_
+                }
+            }
+        }
+
+        function Parse-NeededLine {
+            param(
+                [Parameter(Mandatory=$true)]
+                [string] $Line
+            )
+
+            if ($Line -match '^\s*NEEDED\s*(?<dll>\S+)\s*$') {
+                $Matches.dll
+            } else {
+                throw "Line doesn't match the pattern: $Line"
+            }
+        }
+
+        function Parse-ElfHeaders {
+            param(
+                [Parameter(ValueFromPipeline)]
+                [string[]] $Output
+            )
+
+            process {
+                $Output | Select-String 'NEEDED' -SimpleMatch -CaseSensitive | %{
+                    Parse-NeededLine $_
+                }
+            }
+        }
+
+        function Get-LinkedLibraries {
+            param(
+                [Parameter(Mandatory=$true)]
+                [string] $ExePath
+            )
+
+            $objdump = 'objdump'
+            if ($env:CI_HOST_WINDOWS) {
+                $objdump = 'C:\ProgramData\chocolatey\bin\objdump.exe'
+            }
+
+            if ($env:CI_TARGET_PE) {
+                & $objdump -x $ExePath | Parse-PeHeaders | echo
+            }
+            if ($env:CI_TARGET_ELF) {
+                & $objdump -x $ExePath | Parse-ElfHeaders | echo
+            }
+        }
+
+        function Do-ValidateLinkedLibraries {
+            param(
+                [Parameter(Mandatory=$true)]
+                [ValidateNotNull()]
+                [string[]] $Actual,
+
+                [Parameter(Mandatory=$true)]
+                [ValidateNotNull()]
+                [string[]] $Required,
+
+                [Parameter(Mandatory=$true)]
+                [ValidateNotNull()]
+                [string[]] $Optional
+            )
+
+            echo 'Linked libraries:'
+            echo $Actual
+
+            $missing = $Required | ?{$_ -notin $Actual}
+
+            if ($missing.Count -gt 0) {
+                throw "Doesn't link to the following libraries: $($missing -join ', ')"
+            }
+
+            $unexpected = $Actual | ?{$_ -notin $Required -and $_ -notin $Optional}
+
+            if ($unexpected.Count -gt 0) {
+                throw "Links to the following unexpected libraries: $($unexpected -join ', ')"
+            }
+        }
+
+        function Validate-LinkedLibraries {
+            param(
+                [Parameter(Mandatory=$true)]
+                [ValidateNotNull()]
+                [string[]] $Actual
+            )
+
+            $windows_required = @('KERNEL32.dll')
+            if ($env:CI_MINGW) {
+                $windows_required += 'msvcrt.dll'
+            }
+            # Linking libstdc++ statically on Cygwin is broken, see the
+            # cygwin_static_libstdc++.yml workflow.
+            $cygwin_required = $windows_required + @('cygwin1.dll','cygstdc++-6.dll')
+            $linux_required = @('libc.so.6')
+
+            $windows_optional = @('baz.dll')
+            if ($env:CI_MINGW) {
+                $windows_optional = @('libbaz.dll','USER32.dll')
+            }
+            $cygwin_optional = @('cygbaz.dll')
+            $linux_optional = @('libbaz.so','ld-linux.so.2','ld-linux-x86-64.so.2','libm.so.6')
+
+            if ($env:CI_TARGET_CYGWIN) {
+                Do-ValidateLinkedLibraries `
+                    -Actual $Actual `
+                    -Required $cygwin_required `
+                    -Optional $cygwin_optional
+            } elseif ($env:CI_TARGET_WINDOWS) {
+                Do-ValidateLinkedLibraries `
+                    -Actual $Actual `
+                    -Required $windows_required `
+                    -Optional $windows_optional
+            } elseif ($env:CI_TARGET_LINUX) {
+                Do-ValidateLinkedLibraries `
+                    -Actual $Actual `
+                    -Required $linux_required `
+                    -Optional $linux_optional
+            } else {
+                throw 'Where am I?'
+            }
+        }
+
+        $exe_path = (Join-Path $path 'bin' 'foo') + $env:CI_EXE_EXT
+        $libraries = Get-LinkedLibraries $exe_path
+        Validate-LinkedLibraries $libraries
+      shell: pwsh
diff --git a/.github/actions/check-symbols/action.yml b/.github/actions/check-symbols/action.yml
new file mode 100644
index 0000000..7428be3
--- /dev/null
+++ b/.github/actions/check-symbols/action.yml
@@ -0,0 +1,46 @@
+name: Check symbols
+description: Check debug symbols
+inputs:
+  path:
+    description: Installation directory
+    required: true
+  expected:
+    description: Expected symbols
+    required: true
+runs:
+  using: composite
+  steps:
+    - run: |
+        $install_dir = '${{ inputs.path }}'
+        $bin_dir = Join-Path $install_dir 'bin'
+        $lib_dir = Join-Path $install_dir 'lib'
+
+        $script_path = if ($env:CI_TARGET_ELF) {
+            Join-Path $env:GITHUB_WORKSPACE '.ci' 'verify_symbols.sh'
+        } else {
+            throw "Verifying symbols for PE executables is not implemented"
+        }
+
+        ConvertFrom-Json '${{ inputs.expected }}' | %{
+            $target = $_.target
+            $type = $_.type
+
+            switch -Exact ($type) {
+                'exe' {
+                    $file = $target + $env:CI_EXE_EXT
+                    $path = Join-Path $bin_dir $file
+                }
+                'dll' {
+                    $file = $env:CI_DLL_PREFIX + $target + $env:CI_DLL_EXT
+                    $path = if ($env:CI_DLL_IN_BIN) {
+                        Join-Path $bin_dir $file
+                    } else {
+                        Join-Path $lib_dir $file
+                    }
+                }
+                default { throw "Unrecognized type: $type" }
+            }
+
+            & $script_path $path $_.symbols
+        }
+      shell: pwsh
diff --git a/.github/actions/common-variables/action.yml b/.github/actions/common-variables/action.yml
new file mode 100644
index 0000000..3d40cdd
--- /dev/null
+++ b/.github/actions/common-variables/action.yml
@@ -0,0 +1,85 @@
+name: Set common variables
+description: Set common run variables
+inputs:
+  toolset:
+    description: Toolset used
+    required: true
+  cygwin:
+    description: Targeting Cygwin
+    required: false
+    default: 0
+runs:
+  using: composite
+  steps:
+    - run: |
+        New-Variable toolset -Value '${{ inputs.toolset }}' -Option Constant
+        New-Variable cygwin -Value ('${{ inputs.cygwin }}' -eq '1') -Option Constant
+
+        New-Variable os -Value '${{ runner.os }}' -Option Constant
+
+        New-Variable host_linux -Value ($os -eq 'Linux') -Option Constant
+        New-Variable host_cygwin -Value $cygwin -Option Constant
+        New-Variable host_windows -Value ($os -eq 'Windows' -and !$host_cygwin) -Option Constant
+
+        New-Variable mingw -Value ($toolset -eq 'mingw' -or ($host_windows -and $toolset -eq 'gcc')) -Option Constant
+
+        New-Variable target_linux -Value ($host_linux -and !$mingw) -Option Constant
+        New-Variable target_cygwin -Value ($host_cygwin -and !$mingw) -Option Constant
+        New-Variable target_windows -Value ($mingw -or $host_windows) -Option Constant
+
+        New-Variable target_pe -Value ($target_windows -or $target_cygwin) -Option Constant
+        New-Variable target_elf -Value $target_linux -Option Constant
+
+        function Set-BoolVar {
+            param(
+                [Parameter(Mandatory=$true)]
+                [string] $name,
+                [Parameter(Mandatory=$true)]
+                [bool] $value
+            )
+
+            $str_value = if ($value) { '1' } else { '' }
+            $msg = "$name=$str_value"
+            echo $msg
+            echo $msg >> $env:GITHUB_ENV
+        }
+
+        function Set-StrVar {
+            param(
+                [Parameter(Mandatory=$true)]
+                [string] $name,
+                [string] $value
+            )
+
+            $msg = "$name=$value"
+            echo $msg
+            echo $msg >> $env:GITHUB_ENV
+        }
+
+        Set-BoolVar 'CI_HOST_LINUX' $host_linux
+        Set-BoolVar 'CI_HOST_CYGWIN' $host_cygwin
+        Set-BoolVar 'CI_HOST_WINDOWS' $host_windows
+        Set-BoolVar 'CI_MINGW' $mingw
+        Set-BoolVar 'CI_TARGET_LINUX' $target_linux
+        Set-BoolVar 'CI_TARGET_CYGWIN' $target_cygwin
+        Set-BoolVar 'CI_TARGET_WINDOWS' $target_windows
+
+        Set-BoolVar 'CI_TARGET_PE' $target_pe
+        Set-BoolVar 'CI_TARGET_ELF' $target_elf
+
+        $lib_prefix = 'lib'
+        $lib_ext = if ($target_windows -and -not $mingw) { '.lib' } else { '.a' }
+
+        $dll_prefix = if ($target_windows -and -not $mingw) { '' } elseif ($target_cygwin) { 'cyg' } else { 'lib' }
+        $dll_ext = if ($target_windows -or $target_cygwin) { '.dll' } else { '.so' }
+
+        $exe_ext = if ($target_pe) { '.exe' } else { '' }
+
+        Set-StrVar 'CI_LIB_PREFIX' $lib_prefix
+        Set-StrVar 'CI_LIB_EXT' $lib_ext
+        Set-StrVar 'CI_DLL_PREFIX' $dll_prefix
+        Set-StrVar 'CI_DLL_EXT' $dll_ext
+        Set-StrVar 'CI_EXE_EXT' $exe_ext
+
+        Set-BoolVar 'CI_DLL_IN_BIN' $target_pe
+      shell: pwsh
diff --git a/.github/actions/download-boost/action.yml b/.github/actions/download-boost/action.yml
new file mode 100644
index 0000000..fc0be88
--- /dev/null
+++ b/.github/actions/download-boost/action.yml
@@ -0,0 +1,40 @@
+name: Download Boost
+description: Download & unpack Boost
+inputs:
+  boost-version:
+    description: 'Boost version'
+    required: true
+runs:
+  using: composite
+  steps:
+    - run: echo 'BOOST_VERSION=${{ inputs.boost-version }}' >> $env:GITHUB_ENV
+      shell: pwsh
+    - run: |
+        $parent_dir = Split-Path $env:GITHUB_WORKSPACE
+        $unpack_dir = Join-Path $parent_dir 'boost'
+        echo "BOOST_UNPACK_DIR=$unpack_dir" >> $env:GITHUB_ENV
+      shell: pwsh
+    - run: |
+        $dir_name = "boost_$($env:BOOST_VERSION.Replace('.', '_'))"
+        $dir = Join-Path $env:BOOST_UNPACK_DIR $dir_name
+        echo "BOOST_DIR=$dir" >> $env:GITHUB_ENV
+      shell: pwsh
+    - run: |
+        echo ''
+        echo '----------------------------------------------------------------'
+        echo "BOOST_VERSION:    $env:BOOST_VERSION"
+        echo "BOOST_UNPACK_DIR: $env:BOOST_UNPACK_DIR"
+        echo "BOOST_DIR:        $env:BOOST_DIR"
+        echo '----------------------------------------------------------------'
+        New-Item $env:BOOST_UNPACK_DIR -Type Directory | Out-Null
+
+        $python = 'python'
+        $unpack_dir = $env:BOOST_UNPACK_DIR
+
+        if ($env:CI_HOST_CYGWIN) {
+            $python = 'python3'
+            $unpack_dir = cygpath.exe -ua $unpack_dir
+        }
+
+        & $python -m project.boost.download --unpack $unpack_dir -- $env:BOOST_VERSION
+      shell: pwsh
diff --git a/.github/actions/run-example-boost/action.yml b/.github/actions/run-example-boost/action.yml
new file mode 100644
index 0000000..0dd9f44
--- /dev/null
+++ b/.github/actions/run-example-boost/action.yml
@@ -0,0 +1,45 @@
+name: Run examples/boost
+description: Run examples/boost
+inputs:
+  path:
+    description: Installation directory
+    required: true
+runs:
+  using: composite
+  steps:
+    - run: |
+        New-Variable path -Value '${{ inputs.path }}' -Option Constant
+
+        if ($env:CI_HOST_LINUX -and -not $env:CI_TARGET_LINUX) {
+            echo 'Not going to do that on Linux/MinGW'
+            exit
+        }
+
+        $relative_test = 'test.txt'
+        $absolute_test = Join-Path (Get-Location).Path 'test.txt'
+
+        $exe_path = (Join-Path $path 'bin' 'foo')
+        if (-not $env:CI_TARGET_CYGWIN) {
+            $exe_path += $env:CI_EXE_EXT
+        }
+
+        $argv0 = $exe_path
+        if ($env:CI_TARGET_CYGWIN) {
+            # Apparently, Cygwin programs convert argv[0] when executing native
+            # programs or being executed by them.
+            $argv0 = cygpath.exe -ua $argv0
+        }
+
+        $actual = & $exe_path $relative_test
+
+        echo 'Actual output:'
+        echo $actual
+
+        $expected = $argv0,$absolute_test
+        echo 'Expected output:'
+        echo $expected
+
+        if (Compare-Object $actual $expected -CaseSensitive) {
+            throw 'Unexpected output'
+        }
+      shell: pwsh
diff --git a/.github/actions/run-example/action.yml b/.github/actions/run-example/action.yml
new file mode 100644
index 0000000..5300ab9
--- /dev/null
+++ b/.github/actions/run-example/action.yml
@@ -0,0 +1,28 @@
+name: Run example project
+description: Run example project
+inputs:
+  path:
+    description: Installation directory
+    required: true
+runs:
+  using: composite
+  steps:
+    - run: |
+        New-Variable path -Value '${{ inputs.path }}' -Option Constant
+
+        if ($env:CI_HOST_LINUX -and -not $env:CI_TARGET_LINUX) {
+            echo 'Not going to do that on Linux/MinGW'
+            exit
+        }
+
+        if ($env:CI_TARGET_LINUX) {
+            $lib = Join-Path $path 'lib'
+            if (Test-Path $lib) {
+                $lib = Resolve-Path $lib
+                $env:LD_LIBRARY_PATH = $lib
+            }
+        }
+        $exe_path = (Join-Path $path 'bin' 'foo') + $env:CI_EXE_EXT
+        echo "Executable path: $exe_path"
+        & $exe_path
+      shell: pwsh
diff --git a/.github/actions/software-environment/action.yml b/.github/actions/software-environment/action.yml
new file mode 100644
index 0000000..c8a416b
--- /dev/null
+++ b/.github/actions/software-environment/action.yml
@@ -0,0 +1,63 @@
+name: Set up software environment
+description: Set up software paths and versions
+inputs:
+  toolset:
+    description: Toolset to use
+    required: true
+  platform:
+    description: Target platform
+    required: false
+    default: x64
+runs:
+  using: composite
+  steps:
+    - run: |
+        if ($env:CI_HOST_WINDOWS) {
+            echo 'C:\Program Files\CMake\bin' >> $env:GITHUB_PATH
+        }
+      shell: pwsh
+    - run: |
+        echo '------------------------------------------------------------'
+        echo 'PATH'
+        echo '------------------------------------------------------------'
+        echo $env:PATH.Split([IO.Path]::PathSeparator)
+      shell: pwsh
+    - run: |
+        function Print-Info {
+            param(
+                [Parameter(Mandatory=$true)]
+                [string] $name,
+                [Parameter(Mandatory=$true)]
+                [string] $exe
+            )
+
+            echo ''
+            echo '------------------------------------------------------------'
+            echo $name
+            echo '------------------------------------------------------------'
+            $full_path = Get-Command $exe -ErrorAction SilentlyContinue
+            if ($full_path) {
+                $full_path = $full_path.Path
+                echo "Location: $full_path"
+                echo 'Version info:'
+                & $full_path --version
+            } else {
+                echo "Executable '$name' couldn't be found!"
+            }
+        }
+
+        $python = 'python'
+        if ($env:CI_HOST_CYGWIN) {
+            $python = 'python3'
+        }
+
+        Print-Info 'python' $python
+        Print-Info 'cmake' 'cmake'
+        Print-Info 'make' 'make'
+        Print-Info 'mingw32-make' 'mingw32-make'
+        Print-Info 'g++' 'g++'
+        Print-Info 'clang++' 'clang++'
+        Print-Info 'clang-cl' 'clang-cl'
+        Print-Info 'i686-w64-mingw32-g++' 'i686-w64-mingw32-g++'
+        Print-Info 'x86_64-w64-mingw32-g++' 'x86_64-w64-mingw32-g++'
+      shell: pwsh
diff --git a/.github/workflows/boost_clang_windows.yml b/.github/workflows/boost_clang_windows.yml
new file mode 100644
index 0000000..62c2cb5
--- /dev/null
+++ b/.github/workflows/boost_clang_windows.yml
@@ -0,0 +1,143 @@
+# This basically tests two things.
+#
+#   * If, instead of some kind of MinGW-born ar & ranlib, you only have
+#     upstream LLVM distribution on Windows, you wouldn't be able to use
+#     toolset=clang until 1.66.0.
+#   * toolset=clang-win is broken until 1.69.0.
+
+name: Boost & Clang on Windows
+
+on:
+  push:
+  pull_request:
+  schedule:
+    # Weekly, at 5:30 AM on Saturday (somewhat randomly chosen).
+    - cron: '30 5 * * 6'
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: windows-2019
+
+    strategy:
+      fail-fast: false
+      matrix:
+        toolset: [clang, clang-cl]
+        boost-version: [1.63.0, 1.64.0, 1.65.1, 1.66.0, 1.67.0, 1.68.0, 1.69.0, 1.70.0, 1.71.0, 1.74.0]
+        include:
+          - {toolset: clang, b2_toolset: clang}
+          - {toolset: clang-cl, b2_toolset: clang-win}
+
+    name: '${{ matrix.toolset }} / ${{ matrix.boost-version }}'
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Clean up PATH
+        uses: egor-tensin/cleanup-path@v1
+        if: runner.os == 'Windows'
+
+      - name: Set common variables
+        uses: ./.github/actions/common-variables
+        with:
+          toolset: '${{ matrix.toolset }}'
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.x'
+
+      - name: Install Clang
+        uses: egor-tensin/setup-clang@v1
+
+      - name: Set up software environment
+        uses: ./.github/actions/software-environment
+        with:
+          toolset: ${{ matrix.toolset }}
+
+      - name: Download Boost
+        uses: ./.github/actions/download-boost
+        with:
+          boost-version: ${{ matrix.boost-version }}
+
+      - name: Bootstrap Boost
+        run: |
+          cd $env:BOOST_DIR
+          .\bootstrap.bat
+        continue-on-error: true
+
+      - name: Check that Boost was bootstrapped
+        uses: ./.github/actions/check-boost-bootstrapped
+
+      - name: Write toolset-config.jam (clang)
+        run: |
+          echo 'using ${{ matrix.b2_toolset }} : : clang++.exe : <archiver>llvm-ar <ranlib>llvm-ranlib ;' > "$env:BOOST_DIR\toolset-config.jam"
+        if: matrix.toolset == 'clang'
+      - name: Write toolset-config.jam (clang-cl)
+        run: |
+          echo 'using ${{ matrix.b2_toolset }} ;' > "$env:BOOST_DIR\toolset-config.jam"
+        if: matrix.toolset == 'clang-cl'
+
+      - name: Build Boost.Filesystem
+        run: |
+          cd $env:BOOST_DIR
+
+          $stagedir = "stage"
+          $librarydir = "$env:BOOST_DIR\$stagedir\lib"
+          echo "BOOST_LIBRARYDIR=$librarydir" >> $env:GITHUB_ENV
+
+          .\b2.exe                     `
+              "--stagedir=$stagedir"   `
+              --layout=system          `
+              --dump-configuration     `
+              address-model=64         `
+              "--user-config=$env:BOOST_DIR\toolset-config.jam" `
+              variant=debug            `
+              link=static              `
+              runtime-link=static      `
+              -d2 --dump-configuration `
+              --with-filesystem        `
+              --with-system
+        continue-on-error: true
+
+      - name: Boost.Filesystem failed to build
+        run: $(Test-Path "$env:BOOST_LIBRARYDIR\libboost_filesystem.lib" -Type Leaf) -and $(throw "libboost_filesystem.lib was build?!")
+        if: |
+          (matrix.toolset == 'clang' && matrix.boost-version < '1.66.0') || (matrix.toolset == 'clang-cl' && matrix.boost-version < '1.69.0')
+      - id: boost_filesystem_built
+        name: Boost.Filesystem was built
+        run: $(Test-Path "$env:BOOST_LIBRARYDIR\libboost_filesystem.lib" -Type Leaf) -or $(throw "libboost_filesystem.lib wasn't found")
+        if: |
+          !((matrix.toolset == 'clang' && matrix.boost-version < '1.66.0') || (matrix.toolset == 'clang-cl' && matrix.boost-version < '1.69.0'))
+
+      # Check that we can link to the built libraries.
+      - name: Build foo.exe using clang
+        run: |
+          clang++.exe                   `
+              "-I$env:BOOST_DIR"        `
+              -D BOOST_ALL_NO_LIB=1     `
+              "-L$env:BOOST_LIBRARYDIR" `
+              -llibboost_filesystem     `
+              -llibboost_system         `
+              -o foo.exe                `
+              examples/boost/foo.cpp
+        if: steps.boost_filesystem_built.conclusion == 'success' && matrix.toolset == 'clang'
+
+      - name: Build foo.exe using clang-cl
+        run: |
+          clang-cl.exe                `
+              /EHsc                   `
+              /MTd                    `
+              "/I$env:BOOST_DIR"      `
+              /D BOOST_ALL_NO_LIB=1   `
+              "/Fefoo.exe"            `
+              examples/boost/foo.cpp  `
+              libboost_filesystem.lib `
+              libboost_system.lib     `
+              /link "/LIBPATH:$env:BOOST_LIBRARYDIR"
+        if: steps.boost_filesystem_built.conclusion == 'success' && matrix.toolset == 'clang-cl'
+
+      - name: foo.exe
+        run: .\foo.exe
+        if: steps.boost_filesystem_built.conclusion == 'success'
diff --git a/.github/workflows/boost_toolsets.yml b/.github/workflows/boost_toolsets.yml
new file mode 100644
index 0000000..1319264
--- /dev/null
+++ b/.github/workflows/boost_toolsets.yml
@@ -0,0 +1,222 @@
+name: Boost (toolsets)
+
+on:
+  push:
+  pull_request:
+  schedule:
+    # Weekly, at 5:30 AM on Saturday (somewhat randomly chosen).
+    - cron: '30 5 * * 6'
+  workflow_dispatch:
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        boost-version: [1.58.0, 1.65.0, 1.72.0]
+        toolset: [auto, clang, clang-cl, gcc, mingw, msvc]
+        cygwin: [0, 1]
+        os: [ubuntu-18.04, windows-2016, windows-2019]
+
+        include:
+          # Prettier run names.
+          - {os: windows-2019, name: VS 2019}
+          - {os: windows-2016, name: VS 2017}
+          - {os: ubuntu-18.04, name: Ubuntu}
+          - {cygwin: 1, name: Cygwin}
+          # Target platform.
+          - {boost-version: 1.58.0, platform: x64}
+          - {boost-version: 1.65.0, platform: x86}
+          - {boost-version: 1.72.0, platform: x64}
+          # Configuration.
+          - {boost-version: 1.58.0, configuration: Debug}
+          - {boost-version: 1.65.0, configuration: MinSizeRel}
+          - {boost-version: 1.72.0, configuration: Release}
+
+          # Some Boost libraries commonly used by me.
+          - libraries: filesystem program_options regex system test
+          # On Windows, clang fails to build Boost.Test prior to version 1.61
+          # with the following error:
+          #
+          #     .\boost/test/impl/execution_monitor.ipp:1134:20: error: cannot compile this 'this' captured by SEH yet
+          #
+          # This was fixed for 1.61 in this commit:
+          # https://github.com/boostorg/test/commit/c94ef6982e2ebe77f9376579547c228f0d62e45f.
+          # On Linux/Cygwin, everything should be fine though.
+          - toolset: clang
+            boost-version: 1.58.0
+            os: windows-2019
+            libraries: filesystem program_options regex system
+          - toolset: clang
+            boost-version: 1.58.0
+            os: windows-2016
+            libraries: filesystem program_options regex system
+        exclude:
+          # Ubuntu: no MSVC/clang-cl/Cygwin.
+          - {os: ubuntu-18.04, toolset: msvc}
+          - {os: ubuntu-18.04, toolset: clang-cl}
+          - {os: ubuntu-18.04, cygwin: 1}
+          # Cygwin: no MSVC/clang-cl.
+          - {cygwin: 1, toolset: msvc}
+          - {cygwin: 1, toolset: clang-cl}
+          # Cygwin is the same on Windows Server 2016 & 2019.
+          - {os: windows-2016, cygwin: 1}
+          # clang-cl is only supported by Boost.Build since 1.69 (see the
+          # boost_clang_windows.yml workflow).
+          - {toolset: clang-cl, boost-version: 1.58.0}
+          - {toolset: clang-cl, boost-version: 1.65.0}
+
+    runs-on: '${{ matrix.os }}'
+
+    name: '${{ matrix.boost-version }} / ${{ matrix.toolset }} / ${{ matrix.name }}'
+
+    # 1) I have no idea why, but GCC 10.2 fails to build Boost.Filesystem with
+    #    the following errors:
+    #
+    #        libs\filesystem\src\path.cpp:36:11: fatal error: windows_file_codecvt.hpp: No such file or directory
+    #           36 | # include "windows_file_codecvt.hpp"
+    #              |           ^~~~~~~~~~~~~~~~~~~~~~~~~~
+    #        compilation terminated.
+    #        libs\filesystem\src\windows_file_codecvt.cpp:25:10: fatal error: windows_file_codecvt.hpp: No such file or directory
+    #           25 | #include "windows_file_codecvt.hpp"
+    #              |          ^~~~~~~~~~~~~~~~~~~~~~~~~~
+    #        compilation terminated.
+    #
+    #    This seems to be a compiler bug, since the file is _definitely_ there,
+    #    and Clang 8.0.1 builds it successfully.  This only applies to Boost
+    #    versions up to and including 1.60.0 for some reason.  I can easily
+    #    reproduce this locally.  TODO: remove when GCC on Cygwin is treated
+    #    with a bugfix to this?
+    #
+    # 2) 32-bit Cygwin fucking sucks.  In many ways actually, but the real
+    #    reason was the incomprehensible
+    #
+    #        undefined reference to `__chkstk_ms'
+    #
+    #    error when building with Clang.
+    continue-on-error: ${{
+            (matrix.cygwin == '1' && matrix.boost-version == '1.58.0'
+                && (matrix.toolset == 'auto'
+                    || matrix.toolset == 'gcc'
+                    || matrix.toolset == 'mingw'))
+            || (matrix.cygwin == '1' && matrix.platform == 'x86')
+        }}
+
+    defaults:
+      run:
+        shell: pwsh
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Clean up PATH
+        uses: egor-tensin/cleanup-path@v1
+        if: runner.os == 'Windows'
+
+      - name: Set common variables
+        uses: ./.github/actions/common-variables
+        with:
+          toolset: '${{ matrix.toolset }}'
+          cygwin: '${{ matrix.cygwin }}'
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.x'
+        if: '!env.CI_HOST_CYGWIN'
+
+      - name: Install Cygwin
+        uses: egor-tensin/setup-cygwin@v3
+        with:
+          platform: '${{ matrix.platform }}'
+          packages: cmake make python3
+          hardlinks: 1
+        if: env.CI_HOST_CYGWIN
+
+      - name: Install GCC
+        uses: egor-tensin/setup-gcc@v1
+        with:
+          cygwin: '${{ matrix.cygwin }}'
+          platform: '${{ matrix.platform }}'
+          hardlinks: 1
+        if: env.CI_HOST_CYGWIN || (env.CI_HOST_LINUX && (matrix.toolset == 'auto' || matrix.toolset == 'gcc'))
+
+      - name: Install Clang
+        uses: egor-tensin/setup-clang@v1
+        with:
+          cygwin: '${{ matrix.cygwin }}'
+          platform: '${{ matrix.platform }}'
+          hardlinks: 1
+        if: matrix.toolset == 'clang' || matrix.toolset == 'clang-cl'
+
+      - name: Install MinGW
+        uses: egor-tensin/setup-mingw@v2
+        with:
+          cygwin: '${{ matrix.cygwin }}'
+          platform: '${{ matrix.platform }}'
+          hardlinks: 1
+        # toolset == 'clang' needs some kind of make, e.g. mingw32-make:
+        if: env.CI_MINGW || (matrix.toolset == 'clang' && env.CI_HOST_WINDOWS)
+
+      - name: Set up software environment
+        uses: ./.github/actions/software-environment
+        with:
+          toolset: '${{ matrix.toolset }}'
+          platform: '${{ matrix.platform }}'
+
+      - name: Set up Visual Studio
+        uses: egor-tensin/vs-shell@v2
+        with:
+          arch: '${{ matrix.platform }}'
+        if: matrix.toolset == 'clang-cl' && env.CI_HOST_WINDOWS
+
+      - name: Download Boost
+        uses: ./.github/actions/download-boost
+        with:
+          boost-version: '${{ matrix.boost-version }}'
+
+      - name: Build Boost
+        uses: ./.github/actions/build-boost
+        with:
+          toolset: '${{ matrix.toolset }}'
+          libraries: '${{ matrix.libraries }}'
+          platform: '${{ matrix.platform }}'
+          configuration: '${{ matrix.configuration }}'
+        continue-on-error: true
+
+      - name: Check that Boost was bootstrapped
+        uses: ./.github/actions/check-boost-bootstrapped
+
+      - name: Check that Boost libraries were built
+        uses: ./.github/actions/check-boost-libraries
+        with:
+          libraries: '${{ matrix.libraries }}'
+          platform: '${{ matrix.platform }}'
+          configuration: '${{ matrix.configuration }}'
+
+      - name: Build examples/boost
+        id: build_example
+        uses: ./.github/actions/build-example
+        with:
+          src-dir: examples/boost
+          boost-dir: '${{ env.BOOST_DIR }}'
+          toolset: '${{ matrix.toolset }}'
+          platform: '${{ matrix.platform }}'
+          configuration: '${{ matrix.configuration }}'
+
+      - name: Verify runtime library linkage
+        uses: ./.github/actions/check-runtime-library
+        with:
+          path: '${{ steps.build_example.outputs.install-dir }}'
+
+      - name: Verify architecture
+        uses: ./.github/actions/check-arch
+        with:
+          path: '${{ steps.build_example.outputs.install-dir }}'
+          expected: '${{ matrix.platform }}'
+
+      - name: Run examples/boost
+        uses: ./.github/actions/run-example-boost
+        with:
+          path: '${{ steps.build_example.outputs.install-dir }}'
diff --git a/.github/workflows/cygwin_static_libstdc++.yml b/.github/workflows/cygwin_static_libstdc++.yml
new file mode 100644
index 0000000..156b111
--- /dev/null
+++ b/.github/workflows/cygwin_static_libstdc++.yml
@@ -0,0 +1,81 @@
+# -static-libstdc++ is broken on Cygwin for some reason, as this workflow tries
+# to demonstrate.  I don't know why exactly, but I'm not the only one with this
+# problem:
+#
+#   * https://stackoverflow.com/q/46854365/514684
+#   * https://sourceforge.net/p/stlplus/discussion/345536/thread/48c7fc9c17/?limit=25
+
+name: Cygwin & -static-libstdc++
+
+on:
+  push:
+  pull_request:
+  schedule:
+    # Weekly, at 5:30 AM on Saturday (somewhat randomly chosen).
+    - cron: '30 5 * * 6'
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: windows-2019
+
+    name: Test
+
+    defaults:
+      run:
+        shell: pwsh
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Clean up PATH
+        uses: egor-tensin/cleanup-path@v1
+        if: runner.os == 'Windows'
+
+      - name: Set common variables
+        uses: ./.github/actions/common-variables
+        with:
+          toolset: '${{ matrix.toolset }}'
+          cygwin: 1
+
+      - name: Install Cygwin
+        uses: egor-tensin/setup-cygwin@v3
+
+      - name: Install GCC
+        uses: egor-tensin/setup-gcc@v1
+        with:
+          cygwin: 1
+
+      - name: Set up software environment
+        uses: ./.github/actions/software-environment
+        with:
+          toolset: gcc
+
+      - name: test.cpp
+        run: |
+          $src = @"
+          #include <stdexcept>
+
+          int main() {
+              std::runtime_error x{"x"};
+              std::runtime_error y{x};
+              return 0;
+          }
+          "@
+
+          echo $src > test.cpp
+
+      - name: Build w/ -static-libstdc++
+        run: C:\tools\cygwin\bin\g++.exe -static-libstdc++ -o test test.cpp
+        continue-on-error: true
+
+      - name: Should fail
+        run: $(Test-Path test.exe -Type Leaf) -and $(throw "test.exe shouldn't have been built")
+
+      - name: Build w/ --allow-multiple-definition
+        run: C:\tools\cygwin\bin\g++.exe '-Wl,--allow-multiple-definition' -static-libstdc++ -o test test.cpp
+        continue-on-error: true
+
+      - name: Should succeed
+        run: $(Test-Path test.exe -Type Leaf) -or $(throw "test.exe should have been built")
diff --git a/.github/workflows/example_toolsets.yml b/.github/workflows/example_toolsets.yml
new file mode 100644
index 0000000..cb336aa
--- /dev/null
+++ b/.github/workflows/example_toolsets.yml
@@ -0,0 +1,168 @@
+name: Examples (toolsets)
+
+on:
+  push:
+  pull_request:
+  schedule:
+    # Weekly, at 5:30 AM on Saturday (somewhat randomly chosen).
+    - cron: '30 5 * * 6'
+  workflow_dispatch:
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        example: [simple, static, dynamic]
+        toolset: [auto, clang, clang-cl, gcc, mingw, msvc]
+        cygwin: [0, 1]
+        os: [ubuntu-18.04, windows-2016, windows-2019]
+
+        include:
+          # Prettier run names.
+          - {os: windows-2019, name: VS 2019}
+          - {os: windows-2016, name: VS 2017}
+          - {os: ubuntu-18.04, name: Ubuntu}
+          - {cygwin: 1, name: Cygwin}
+          # Target platform.
+          - {example: simple, platform: x64}
+          - {example: static, platform: x86}
+          - {example: dynamic, platform: x64}
+          # Configuration.
+          - {example: simple, configuration: Release}
+          - {example: static, configuration: Debug}
+          - {example: dynamic, configuration: RelWithDebInfo}
+          # Expected symbols.
+          - example: simple
+            symbols:
+              - target: foo
+                type: exe
+                symbols: []
+          - example: static
+            symbols:
+              - target: foo
+                type: exe
+                symbols: [main, bar]
+          - example: dynamic
+            symbols:
+              - target: foo
+                type: exe
+                symbols: [main]
+              - target: baz
+                type: dll
+                symbols: [baz]
+        exclude:
+          # Ubuntu: no MSVC/clang-cl/Cygwin.
+          - {os: ubuntu-18.04, toolset: msvc}
+          - {os: ubuntu-18.04, toolset: clang-cl}
+          - {os: ubuntu-18.04, cygwin: 1}
+          # Cygwin: no MSVC/clang-cl.
+          - {cygwin: 1, toolset: msvc}
+          - {cygwin: 1, toolset: clang-cl}
+          # Cygwin is the same on Windows Server 2016 & 2019.
+          - {os: windows-2016, cygwin: 1}
+
+    runs-on: '${{ matrix.os }}'
+
+    name: '${{ matrix.example }} / ${{ matrix.toolset }} / ${{ matrix.name }}'
+
+    defaults:
+      run:
+        shell: pwsh
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Clean up PATH
+        uses: egor-tensin/cleanup-path@v1
+        if: runner.os == 'Windows'
+
+      - name: Set common variables
+        uses: ./.github/actions/common-variables
+        with:
+          toolset: '${{ matrix.toolset }}'
+          cygwin: '${{ matrix.cygwin }}'
+
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.x'
+        if: '!env.CI_HOST_CYGWIN'
+
+      - name: Install Cygwin
+        uses: egor-tensin/setup-cygwin@v3
+        with:
+          platform: '${{ matrix.platform }}'
+          packages: cmake make python3
+          hardlinks: 1
+        if: env.CI_HOST_CYGWIN
+
+      - name: Install GCC
+        uses: egor-tensin/setup-gcc@v1
+        with:
+          cygwin: '${{ matrix.cygwin }}'
+          platform: '${{ matrix.platform }}'
+          hardlinks: 1
+        if: (env.CI_HOST_LINUX || env.CI_HOST_CYGWIN) && (matrix.toolset == 'auto' || matrix.toolset == 'gcc')
+
+      - name: Install Clang
+        uses: egor-tensin/setup-clang@v1
+        with:
+          cygwin: '${{ matrix.cygwin }}'
+          platform: '${{ matrix.platform }}'
+          hardlinks: 1
+        if: matrix.toolset == 'clang' || matrix.toolset == 'clang-cl'
+
+      - name: Install MinGW
+        uses: egor-tensin/setup-mingw@v2
+        with:
+          cygwin: '${{ matrix.cygwin }}'
+          platform: '${{ matrix.platform }}'
+          hardlinks: 1
+        # toolset == 'clang' needs some kind of make, e.g. mingw32-make:
+        if: env.CI_MINGW || (matrix.toolset == 'clang' && env.CI_HOST_WINDOWS)
+
+      - name: Set up software environment
+        uses: ./.github/actions/software-environment
+        with:
+          toolset: '${{ matrix.toolset }}'
+          platform: '${{ matrix.platform }}'
+
+      - name: Set up Visual Studio
+        uses: egor-tensin/vs-shell@v2
+        with:
+          arch: '${{ matrix.platform }}'
+        if: matrix.toolset == 'clang-cl' && env.CI_HOST_WINDOWS
+
+      - name: Build example project
+        id: build
+        uses: ./.github/actions/build-example
+        with:
+          src-dir: 'examples/${{ matrix.example }}'
+          toolset: '${{ matrix.toolset }}'
+          platform: '${{ matrix.platform }}'
+          configuration: '${{ matrix.configuration }}'
+
+      - name: Verify runtime library linkage
+        uses: ./.github/actions/check-runtime-library
+        with:
+          path: '${{ steps.build.outputs.install-dir }}'
+
+      - name: Verify architecture
+        uses: ./.github/actions/check-arch
+        with:
+          path: '${{ steps.build.outputs.install-dir }}'
+          expected: '${{ matrix.platform }}'
+
+      - name: Run example project
+        uses: ./.github/actions/run-example
+        with:
+          path: '${{ steps.build.outputs.install-dir }}'
+
+      - name: Check symbols
+        uses: ./.github/actions/check-symbols
+        with:
+          path: '${{ steps.build.outputs.install-dir }}'
+          expected: '${{ toJson(matrix.symbols) }}'
+        if: env.CI_TARGET_ELF