Declare string uppercase/lowercase functions unconditionally.

Avoid naming them str*(), because such names are reserved by ISO C.

include/asm/lexer.h

@@ -59,9 +59,7 @@ extern void yyunputbytes(ULONG count);
 
 extern YY_BUFFER_STATE pCurrentBuffer;
 
-#ifdef __GNUC__
-extern void strupr(char *s);
-extern void strlwr(char *s);
-#endif
+extern void upperstring(char *s);
+extern void lowerstring(char *s);
 
 #endif