Fix building sanitizer_linux_libcdep.cc on FreeBSD
Differential Revision: http://reviews.llvm.org/D5166


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@217148 91177308-0d34-0410-b5e6-96231b3b80d8
Intercept _exit() for sanitizers' needs on FreeBSD
Differential Revision: http://reviews.llvm.org/D5171


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@217156 91177308-0d34-0410-b5e6-96231b3b80d8