[libc++] Refactor Windows support headers.

Summary:
This patch refactors and tries to remove as much of the Windows support headers as possible. This is needed because they currently introduce super weird include cycles and dependencies between STL and libc headers.

The changes in this patch are:

* remove `support/win32/support.h` completely. The required parts have either been moved into `support/win32/msvc_support.h` (for `MSVC` only helpers not needed by Clang), or directly into their respective `foo.h` headers.

* Combine `locale_win32.h` and `locale_mgmt_win32.h` into a single headers, this header should only be included within `__locale` or `locale` to avoid include cycles.

* Remove the unneeded parts of `limits_win32.h` and re-name it to `limits_msvc_win32.h` since it's only needed by Clang.

I've tested this patch using Clang on Windows, but I suspect it might technically regress our non-existent support for MSVC. Is somebody able to double check?

This refactor is needed to support upcoming fixes to `<locale>` on Windows.



Reviewers: bcraig, rmaprath, compnerd, EricWF

Reviewed By: EricWF

Subscribers: majnemer, cfe-commits

Differential Revision: https://reviews.llvm.org/D32988

llvm-svn: 302727

1 files changed, 1 insertions, 4 deletions

diff --git a/libcxx/src/string.cpp b/libcxx/src/string.cpp
index cd644330b3a..d7ebdd3e5c9 100644
--- a/libcxx/src/string.cpp
+++ b/libcxx/src/string.cpp
@@ -13,9 +13,6 @@
 #include "cerrno"
 #include "limits"
 #include "stdexcept"
-#ifdef _LIBCPP_MSVCRT
-#include "support/win32/support.h"
-#endif // _LIBCPP_MSVCRT
 #include <stdio.h>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
@@ -430,7 +427,7 @@ get_swprintf()
 #ifndef _LIBCPP_MSVCRT
     return swprintf;
 #else
-    return static_cast<int (__cdecl*)(wchar_t* __restrict, size_t, const wchar_t*__restrict, ...)>(swprintf);
+    return static_cast<int (__cdecl*)(wchar_t* __restrict, size_t, const wchar_t*__restrict, ...)>(_snwprintf);
 #endif
 }