--- a/src/xsetleds.c
+++ b/src/xsetleds.c
@@ -29,8 +29,9 @@
 #include <string.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <ctype.h> /* isalpha() */
 
-#include <xsetleds.h>
+#include "xsetleds.h"
 
 
 struct key keytab[] = {