This removes the include to <sys/limits.h> in grep.c which is not

necessary since grep.h includes it but also replaces that include
with an include to <limits.h> for portability, or something
approaching it.

grep.c

@@ -27,7 +27,6 @@
  */
 
 #include <sys/types.h>
-#include <sys/limits.h>
 #include <sys/stat.h>
 #include <sys/queue.h>
 

grep.h

@@ -27,8 +27,8 @@
  */
 
 #include <sys/types.h>
-#include <sys/limits.h>
 
+#include <limits.h>
 #include <regex.h>
 #include <stdio.h>
 #include <zlib.h>