Fixed compiler warning about re-definitions of system macros

The header "mhd_sys_options.h" controls behaviour of other included
headers and must be always included first (if included).

src/tests/client_server/libtest.c

@@ -23,12 +23,12 @@
  * @brief testing harness with clients against server
  * @author Christian Grothoff
  */
+#include "libtest.h"
 #include <pthread.h>
 #include <stdbool.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
-#include "libtest.h"
 
 /**
  * A semaphore.

src/tests/client_server/libtest_convenience.c

@@ -23,12 +23,12 @@
  * @brief convenience functions for libtest users
  * @author Christian Grothoff
  */
+#include "libtest.h"
 #include <pthread.h>
 #include <stdbool.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
-#include "libtest.h"
 #include <curl/curl.h>
 
 

src/tests/client_server/libtest_convenience_client_request.c

@@ -23,12 +23,12 @@
  * @brief convenience functions implementing clients making requests for libtest users
  * @author Christian Grothoff
  */
+#include "libtest.h"
 #include <pthread.h>
 #include <stdbool.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
-#include "libtest.h"
 #include <curl/curl.h>
 
 

src/tests/client_server/libtest_convenience_server_reply.c

@@ -25,13 +25,13 @@
  *   replies from the server for libtest users
  * @author Christian Grothoff
  */
+#include "libtest.h"
 #include <pthread.h>
 #include <stdbool.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <errno.h>
-#include "libtest.h"
 #include <curl/curl.h>