Index: source/lib/charcnv.c
===================================================================
--- source/lib/charcnv.c	(revision 3909)
+++ source/lib/charcnv.c	(working copy)
@@ -84,6 +84,9 @@
 		}
 		ret = ln;
 	}
+	/* we set back the locale to C to get ASCII-compatible toupper/lower funcions
+	   for now we do not need any other POSIX localisations anyway */
+	setlocale(LC_ALL, "C");
 #endif
 
 	if (!ret || !*ret) ret = "ASCII";