mcstransd: fix and reorder includes

- Sort included header files by their number of path components then
  alphabetically.
- Include unistd.h and sys/types.h only once.
- Include sys/uio.h to get readv() and writev() declarations when
  compiling with musl libc.
- Include poll.h instead of sys/poll.h as building with musl results in
  the following message:

    /usr/lib/musl/include/sys/poll.h:1:2: error: #warning redirecting
    incorrect #include <sys/poll.h> to <poll.h> [-Werror=cpp]
     #warning redirecting incorrect #include <sys/poll.h> to <poll.h>
     ^~~~~~~

Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>

mcstrans/src/mcstransd.c

@@ -1,22 +1,21 @@
 /* Copyright (c) 2006 Trusted Computer Solutions, Inc. */
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <sys/poll.h>
-#include <sys/stat.h>
-#include <sys/un.h>
 #include <errno.h>
+#include <poll.h>
+#include <signal.h>
 #include <stdint.h>
 #include <stdio.h>
-#include <unistd.h>
 #include <stdlib.h>
-#include <signal.h>
 #include <string.h>
 #include <syslog.h>
 #include <unistd.h>
 #include <selinux/selinux.h>
-#include <sys/types.h>
 #include <sys/capability.h>
 #include <sys/resource.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <sys/un.h>
 #include "mcstrans.h"
 
 #ifdef UNUSED