When using binutils's windres, we can instruct it to invoke the preprocessor
in such a way that it writes a depfile, so that dependencies on #included
files are automatically tracked.
Not implemented for MSVC tools, so skip testing it in that case.
Expose depend_files: from the custom_target this creates.
This is the change suggested in #2815, with tests and documentation added.
Fixes#2789 (duplicate #2830)
This also adds a "# noqa: F401" comment on an unused "import lzma",
which we are using it in a try/except block that is being used to
check if the lzma module is importable; of course it is unused.
v2: This turned out to be a little tricky.
mesonbuild/modules/__init__.py had the "unused" import:
from ..interpreterbase import permittedKwargs, noKwargs
However, that meant that the various modules could do things like:
from . import noKwargs # "." is "mesonbuild.modules"
Which breaks when you remove __init__.py's "unused" import. I
could have tagged that import with "# noqa: F401", but instead I
chose to have each of the module import directly from
"..interpreterbase" instead of ".".
When cross compiling with mingw it's problematic to assume that there is
a binary called windres, and having to set it via an environment
variable seems wrong when there is a handy cross-file for just such a
situation.
This patch allows setting windres in the [binaries] section of the cross
file. If the build is a cross build, then the windows module will check
for windres being set in the cross file before checking the WINDRES
environment variable or looking for a windres binary.
Everywhere we use this object, we end up iterating over it and comparing
compiler.get_language() with something. Using a dict is the obvious
choice and simplifies a lot of code.