Don't link libm with -Wl,--as-needed on FreeBSD
Don't link libm with -Wl,--as-needed on FreeBSD

Patch by jbeich (Jan Beich)

Differential Revision: https://reviews.llvm.org/D68051

git-svn-id: f99161ee8ccfe2101cbe1bdda2220bce2ed25485@374037 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/openmp,llvm-mirror/openmp,llvm-mirror/openmp,llvm-mirror/openmp,llvm-mirror/openmp