G M:  Make valarray a little more forgiving to compilers not quite so gifted.  This has no impact on clang.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@190731 91177308-0d34-0410-b5e6-96231b3b80d8
G M: Make shared_ptr a little more gentle for some compilers.  No impact on clang.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@190732 91177308-0d34-0410-b5e6-96231b3b80d8