Index: src/support/win32/locale_win32.cpp
===================================================================
--- src/support/win32/locale_win32.cpp	(revision 177819)
+++ src/support/win32/locale_win32.cpp	(working copy)
@@ -20,6 +20,8 @@
 locale_t uselocale( locale_t newloc )
 {
     locale_t old_locale = _get_current_locale();
+    if ( newloc == NULL )
+        return old_locale;
     // uselocale sets the thread's locale by definition, so unconditionally use thread-local locale
     _configthreadlocale( _ENABLE_PER_THREAD_LOCALE );
     // uselocale sets all categories