tsan: fix freebsd build freebsd does not have /proc/self/environ
tsan: fix freebsd build
freebsd does not have /proc/self/environ



git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@211417 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt