[PATCH] Added assembly functions for x86 asan.

[Evgeniy Stepanov]

  I'm getting this error from clang when linking the test:
    missing .note.GNU-stack section implies executable stack

  I think you need to add the following to .S (compare it with what clang generates for a simple source):
    .section        ".note.GNU-stack","", at progbits

http://llvm-reviews.chandlerc.com/D2819