[PATCH] [compiler-rt] Remove -fomit-frame-pointer from sanitizers CFLAGS

[Kostya Serebryany]

Of course, hide it in a macro, e.g. 
  #define ENABLE_FRAME_POINTERS do {volatile uptr enable_fp = GET_CALLER_PC();"} while (0)

http://reviews.llvm.org/D4305