_STD -> _VSTD to avoid macro clash on windows

llvm-svn: 134190
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: ce48a1137d56d368828d360e5f2a8162bac6517c
diff --git a/include/exception b/include/exception
index 00fc6b8..f418575 100644
--- a/include/exception
+++ b/include/exception
@@ -199,7 +199,7 @@
 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
 {
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    throw __nested<typename remove_reference<_Tp>::type>(_STD::forward<_Tp>(__t));
+    throw __nested<typename remove_reference<_Tp>::type>(_VSTD::forward<_Tp>(__t));
 #endif
 }
 
@@ -218,7 +218,7 @@
 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
 {
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    throw _STD::forward<_Tp>(__t);
+    throw _VSTD::forward<_Tp>(__t);
 #endif
 }