ctype: constify lookup table

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/lib/ctype.c b/lib/ctype.c
index 6ed0468..dffe563 100644
--- a/lib/ctype.c
+++ b/lib/ctype.c
@@ -29,7 +29,7 @@
 
 #include <linux/ctype.h>
 
-unsigned char _ctype[] = {
+const unsigned char _ctype[] = {
 _C,_C,_C,_C,_C,_C,_C,_C,			/* 0-7 */
 _C,_C|_S,_C|_S,_C|_S,_C|_S,_C|_S,_C,_C,		/* 8-15 */
 _C,_C,_C,_C,_C,_C,_C,_C,			/* 16-23 */