style(9): sort #includes

MFC after:	1 week
Sponsored by:	Dell EMC Isilon

lib/libc/gen/getttyent.c

@@ -33,15 +33,15 @@ static char sccsid[] = "@(#)getttyent.c	8.1 (Berkeley) 6/4/93";
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <ttyent.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <ctype.h>
-#include <string.h>
-
 #include <sys/types.h>
 #include <sys/sysctl.h>
 
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ttyent.h>
+
 static char zapchar;
 static FILE *tf;
 static size_t lbsize;