[patch] support for clang compiler

[kaliber]

This patch allows to use clang compiler (native only, no cross compiler). Note that clang still uses gcc for linking, assembler and stdc++ library.

[tqh]

Note that clang still uses gcc for linking, assembler and stdc++ library.

Is this why HAIKU_GCC is introduced? In that case it looks fine to me, but I'm still a bit unexperienced here so I want a second opinion.

[kaliber]

Replying to tqh:

Note that clang still uses gcc for linking, assembler and stdc++ library.

Is this why HAIKU_GCC is introduced?

Yes.

[stippi]

Looks fine to me as well. Ingo may know more about any unwanted implications or side effects.

[tqh]

Tested the configure changes with this:

$ ./configure --build-cross-tools-gcc4 x86 ../buildtools/ --include-gpl-addons --include-patented-code -j3

Unfortunatly it fails after configuring with:

$ jam -a -j3 -q @disk
No `BuildConfig' found in generated/build! 
Run ./configure in the source tree's root directory first! 

Also the help for configure shows clang flag and its description misaligned. Since its only native I suggest it is also mentioned in the description.

[bonefish]

Sorry for the late response. It certainly doesn't harm to have the patch available here for people who are interested in trying it, but ATM I don't see any benefit in actually applying it, particularly because I find the clang/gcc mix not so clean. I'd rather see clang support being added in what I think is the right order, i.e. starting with cross compilation support, and ideally without mixing and matching gcc components.

[waddlesplash]

Clang support has been merged to master.