[libc++] Rename include/support to include/__support

We do ship those headers, so the directory name should not be something
that can potentially conflict with user-defined directories.

Differential Revision: https://reviews.llvm.org/D95956

GitOrigin-RevId: b51756819a85563ae063e98eeb3d6af8e44c8f64
diff --git a/src/locale.cpp b/src/locale.cpp
index f109389..a0209d0 100644
--- a/src/locale.cpp
+++ b/src/locale.cpp
@@ -29,7 +29,7 @@
 #include "cwctype"
 #include "__sso_allocator"
 #if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
-#include "support/win32/locale_win32.h"
+#include "__support/win32/locale_win32.h"
 #elif !defined(__BIONIC__) && !defined(__NuttX__)
 #include <langinfo.h>
 #endif