[LLVMdev] Using thin archives when building llvm

[Rafael Espíndola]

I have just committed support to llvm-ar for creating thin archives.
The idea of thin archives is that they contain just the symbol table
and the path to find the original .o files.

By locally making thin archives the default I was able to build
llvm+lld+clang with them. The total size of the .a files goes from
181,658,164 to 7,116,900 bytes.

Is there any way to do that with cmake without having to have a hacked
llvm-ar? All that is needed is for cmake to run

.../llvm-ar cqT foo.a ....

instead of

.../llvm-ar cq foo.a ....

Thanks,
Rafael