Xing Xue: Some minor changes for IBM XLC++/AIX.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@189623 91177308-0d34-0410-b5e6-96231b3b80d8
Glen:  Remove unneeded _LIBCPP_ALWAYS_INLINE.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@189626 91177308-0d34-0410-b5e6-96231b3b80d8