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  TODO: .ci/Makefile is obsolete now, as well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, 7 insertions, 4 deletions

diff --git a/project/ci/boost.py b/project/ci/boost.py
index c17c9db..3da5c9b 100644
--- a/project/ci/boost.py
+++ b/project/ci/boost.py
@@ -7,8 +7,9 @@ import argparse
 import logging
 import sys
 
-from project.boost.download import DownloadParameters, download
 from project.boost.build import BuildParameters, build
+from project.boost.download import DownloadParameters, download
+from project.boost.toolchain import ToolchainType
 from project.linkage import Linkage
 
 
@@ -27,8 +28,10 @@ def _parse_args(dirs, argv=None):
     parser.add_argument('--runtime-link', metavar='LINKAGE',
                         type=Linkage.parse,
                         help='how the libraries link to the runtime')
-    parser.add_argument('--mingw', action='store_true',
-                        help='build using MinGW-w64')
+    parser.add_argument('--toolset', metavar='TOOLSET',
+                        type=ToolchainType.parse,
+                        help='toolset to use')
+
     parser.add_argument('b2_args', metavar='B2_ARG',
                         nargs='*', default=[],
                         help='additional b2 arguments, to be passed verbatim')
@@ -50,6 +53,6 @@ def build_ci(dirs, argv=None):
                              configurations=(dirs.get_configuration(),),
                              link=args.link,
                              runtime_link=args.runtime_link,
-                             mingw=args.mingw,
+                             toolset=args.toolset,
                              b2_args=args.b2_args)
     build(params)