add wxXLocale class and wxIsxxx_l() and wxToxxx_l() functions (heavily modified and extended patch 1874287)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51632 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/features.h

@@ -74,5 +74,14 @@
     #define wxHAS_NATIVE_TAB_TRAVERSAL
 #endif
 
+/* This is defined when the compiler provides some type of extended locale
+   functions.  Otherwise, we implement them ourselves to only support the
+   'C' locale */
+#if defined(HAVE_LOCALE_T) || wxCHECK_VISUALC_VERSION(8)
+    #define wxHAS_XLOCALE_SUPPORT
+#else
+    #undef wxHAS_XLOCALE_SUPPORT
+#endif
+
 #endif /*  _WX_FEATURES_H_ */