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  TODO: .ci/Makefile is obsolete now, as well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.

1 files changed, 40 insertions, 0 deletions

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