Fix a scanf type mismatch

"%o" takes an unsigned int.

Signed-off-by: Ran Benita <ran234@gmail.com>

src/xkbcomp/xkbscan.l

@@ -69,7 +69,7 @@ extern int yyparse(void);
 
 <S_STR,S_KEY>\\[0-7]{1,3} {
 			/* octal escape sequence */
-			int result;
+			unsigned int result;
 
 			(void) sscanf( yytext + 1, "%o", &result );