Added testing support for cross-MinGW builds.

This adds a build_config that will cross-build a Windows executable
using the MinGW cross-compiler and will also run the unit (i.e.
'rake test') using Wine.

For this to work, I made some modifications to the underlying test
scripts as well as some minor changes to a couple of the tests
themselves.

1 files changed, 91 insertions, 0 deletions

diff --git a/build_config/cross-mingw-winetest.rb b/build_config/cross-mingw-winetest.rb
new file mode 100644
index 000000000..fad06b265
--- /dev/null
+++ b/build_config/cross-mingw-winetest.rb
@@ -0,0 +1,91 @@
+
+# Cross-compile using MinGW and test using Wine.
+#
+# Steps:
+#
+#   1. Install MinGW; 64-bit target seems to work best.
+#
+#   2. Install Wine.
+#
+#   3. Run command:
+#
+#           wine cmd /c echo "Hello world"'
+#
+#      This will confirm that Wine works and will trigger standard
+#      Wine setup, which is slow.
+#
+#   4. Confirm that drive 'z:' is mapped to your root filesystem.
+#      (This is supposed to be a default but it helps to
+#      double-check.)  To confirm, run:
+#
+#           wine cmd /c dir 'z:\\'
+#
+#      This should give you a DOS-style equivalent of 'ls /'.  If not,
+#      you'll need to fix that with winecfg or by adding a symlink to
+#      '~/.wine/dosdevices'.
+#
+#   5. You will likely need to tweak the settings below to work with
+#      your configuration unless it is exactly like one of the platforms
+#      I've tested on (Ubuntu 20.04 or macOS using brew.)
+#
+#   6. Run the build command:
+#
+#           MRUBY_CONFIG=build_config/cross-mingw-winetest.rb rake test
+#
+#      If all goes well, you should now have Windows executables and a
+#      set of passing tests.
+#
+#
+#  Caveats:
+#
+#    1. This works by using a helper script that rewrites test output
+#       to make it look *nix-like and then handing it back to the test
+#       cases.  Some of the existing tests were (slightly) modified to
+#       make this easier but only for the 'full-core' gembox.  Other
+#       gems' bintests may or may not work with the helper script and
+#       may or may not be fixable by extending the script.
+#
+#   2.  MinGW and Wine are both complex and not very consistent so you
+#       will likely need to do some fiddling to get things to work.
+#
+#   3.  This script assumes you are running it on a *nix-style OS.
+#
+#   4.  I recommend building 64-bit targets only.  Building a 32-bit
+#       Windows binary with i686-w64-mingw32 seems to work (at least,
+#       it did for me) but the resulting executable failed a number of
+#       unit tests due to small errors in some floating point
+#       operations.  It's unclear if this indicates more serious problems.
+#
+
+
+MRuby::CrossBuild.new("cross-mingw-winetest") do |conf|
+  conf.toolchain :gcc
+
+  conf.host_target = "x86_64-w64-mingw32"
+
+  # Ubuntu 20
+  conf.cc.command = "#{conf.host_target}-gcc-posix"
+
+  # macOS+Wine from brew
+  #conf.cc.command = "#{conf.host_target}-gcc"
+
+  conf.linker.command = conf.cc.command
+  conf.archiver.command = "#{conf.host_target}-gcc-ar"
+  conf.exts.executable = ".exe"
+
+  # By default, we compile as static as possible to remove runtime
+  # MinGW dependencies; they are probably fixable but it gets
+  # complicated.
+  conf.cc.flags = ['-static']
+  conf.linker.flags += ['-static']
+
+  conf.test_runner do |t|
+    thisdir = File.absolute_path( File.dirname(__FILE__) )
+    t.command = File.join(thisdir, * %w{ helpers wine_runner.rb})
+  end
+
+  conf.gembox "full-core"
+
+  conf.enable_bintest
+  conf.enable_test
+end