Include sys/types.h instead of unistd.h to get uid_t and gid_t.

Add missing include of sys/types.h to a few places.

lib/util/sha2.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013 Todd C. Miller <Todd.Miller@courtesan.com>
+ * Copyright (c) 2013-2015 Todd C. Miller <Todd.Miller@courtesan.com>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -25,6 +25,7 @@
 
 #include <config.h>
 
+#include <sys/types.h>
 #include <stdio.h>
 #ifdef STDC_HEADERS
 # include <stdlib.h>
@@ -57,7 +58,6 @@
 #else
 # include "compat/endian.h"
 #endif
-#include <unistd.h>
 
 #include "sudo_compat.h"
 #include "compat/sha2.h"