fix up yet more annoying signed/unsigned and mixed type errors
diff --git a/shell/hush.c b/shell/hush.c
index ff29974..096b402 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2614,10 +2614,10 @@
 	return 0;
 }
 
-static void mapset(const unsigned char *set, int code)
+static void mapset(const char *set, int code)
 {
-	const unsigned char *s;
-	for (s=set; *s; s++) map[*s] = code;
+	const char *s;
+	for (s=set; *s; s++) map[(int)*s] = code;
 }
 
 static void update_ifs_map(void)