[msan] Fix gethostbyname_r and similar interceptors.

*h_errno is written not on success, but on failure.
In fact, it seems like it can be written even when return value signals
success, so we just unpoison it in all cases.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@197383 91177308-0d34-0410-b5e6-96231b3b80d8
[msan] Relax gethostbyname_r test condition.

Apparently, its return value depends on the glibc version.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@197390 91177308-0d34-0410-b5e6-96231b3b80d8
[msan] Tweak gethostbyname_r interceptor some more.

This is covered by msan_test depending on glibc version and/or resolver setup.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@197484 91177308-0d34-0410-b5e6-96231b3b80d8