Check if -coverage and -fsantize=address can actually link.

On FreeBSD both are broken:
1. Both GCC-4.8 and Clang fail to find libasan with -fsanitize=address
2. Clang fails to find libprofile_rt.a with -coverage
  https://lists.freebsd.org/pipermail/freebsd-toolchain/2013-September/001030.html