mkfs: include-what-you-use header check

Two headers added
 #include <limits.h> // for CHAR_MAX
 #include <stdlib.h> // for exit, EXIT_SUCCESS, getenv, etc

Rest sorted, and nls.h recategorized to be local header.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

disk-utils/mkfs.c

@@ -14,11 +14,14 @@
  */
 
 #include <getopt.h>
+#include <limits.h>
 #include <stdio.h>
-#include <unistd.h>
+#include <stdlib.h>
 #include <string.h>
-#include <nls.h>
+#include <unistd.h>
 
+#include "c.h"
+#include "nls.h"
 #include "xalloc.h"
 
 #ifndef DEFAULT_FSTYPE