Move _LIBCPP_VISIBLE_INLINE from the out-of-line definitions of member
functions to the original declarations, so that Clang will actually
see them. Part of <rdar://problem/11489333>.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@157097 91177308-0d34-0410-b5e6-96231b3b80d8