Add support for generating and using gcc's native dependency files with
the GNU Assembler in addition to the existing C/C++ support.
When the gas and gccdeps tools are loaded, the configure step will test
whether gcc operating on an assembly file supports the -MMD argument.
If so, waf will pass the -MMD argument to .S files assembled with gcc
which will cause it to generate .d dependency files. Waf will then parse
those files for dependency information.
Note: This will only work for assembly files compiled through the gcc
frontend, not with GNU as directly. It also requires assembly files to
use the uppercase .S file extension.
The global value gccdeps was appended to CFLAGS and CXXFLAGS instead of
the actual flags tested against the compiler. This ignored
modifications to the GCCDEPS_FLAGS environment variable and complicated
adding support for additional compilers at the project level.
The find_resource call is slow, so caching the resulting Node object
gives a significant speed up, about twice as fast.
Issue: 1244
Signed-off-by: Thomas Nagy <tnagy2pow10@gmail.com>
