Nico Rieck: Currently _MSC_VER and _WIN32 are used to guard code which is

MSVC-specific, MSVCRT-specific, or Windows-specific. Because Clang can
also define _MSC_VER, and MSVCRT is not necessarily the only C runtime,
these macros should not be used interchangeably.

This patch divides all Windows-related bits into the aforementioned
categories. Two new macros are introduced:

- _LIBCPP_MSVC: Defined when compiling with MSVC. Detected using
  _MSC_VER, excluding Clang.
- _LIBCPP_MSVCRT: Defined when using the Microsoft CRT. This is the default
   when _WIN32 is defined.

This leaves _WIN32 for code using the Windows API.

This also corrects the spelling of _LIBCP_HAS_IS_BASE_OF to _LIBCPP_HAS_IS_BASE_OF.

Nico, please prepare a patch for CREDITS.TXT, thanks.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@187593 91177308-0d34-0410-b5e6-96231b3b80d8

include/vector

@@ -309,14 +309,14 @@ __vector_base_common<__b>::__throw_out_of_range() const
 #endif
 }
 
-#ifdef _MSC_VER
+#ifdef _LIBCPP_MSVC
 #pragma warning( push )
 #pragma warning( disable: 4231 )
-#endif // _MSC_VER
+#endif // _LIBCPP_MSVC
 _LIBCPP_EXTERN_TEMPLATE(class __vector_base_common<true>)
-#ifdef _MSC_VER
+#ifdef _LIBCPP_MSVC
 #pragma warning( pop )
-#endif // _MSC_VER
+#endif // _LIBCPP_MSVC
 
 template <class _Tp, class _Allocator>
 class __vector_base