[submission] gccas

[RJVB (René Bertin)]

Early llvm versions contained a utility called gccas which sat between the llvm-gcc front-end and the llvm assembler.

This proposal recreates a similar script that can be used as an alternative to the as command from port:cctools, invoking the clang assembler instead. It's main purpose is to be used as the default assembler in the GCC ports but it should be possible to use it anywhere a more recent GNU as is required than the one shipped with port:cctools.

I've tested the script after rebuilding port:gcc6 : it allows to build a port like R with -march=native even on my i7 where this would normally lead to errors due to the use of AVX instructions that cctools:as cannot handle.

Note that I'm open to other names for the script and port.

[RJVB (René Bertin)]

Another thing: this could be installed by the clang ports ... but then how to install a wrapper that invokes the system clang?

[RJVB (René Bertin)]

Digging on:

​https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80782

It looks like we should be able to patch gcc/config/darwin.h to force as to call the clang assembler systematically.

I tested using as -q as the assembler and that doesn't cause a single issue with the GCC build.