Include common.h before any system headers.

This should fix some problems building on AIX.

plugins/check_tcp.c

@@ -32,13 +32,12 @@ char *progname;
 const char *copyright = "1999-2014";
 const char *email = "devel@nagios-plugins.org";
 
-#include <ctype.h>
-
 #include "common.h"
 #include "netutils.h"
 #include "utils.h"
 #include "utils_tcp.h"
 
+#include <ctype.h>
 #include <sys/select.h>
 
 #ifdef HAVE_SSL

plugins/negate.c

@@ -35,12 +35,12 @@ const char *email = "devel@nagios-plugins.org";
 
 #define DEFAULT_TIMEOUT 11
 
-#include <ctype.h>
-
 #include "common.h"
 #include "utils.h"
 #include "utils_cmd.h"
 
+#include <ctype.h>
+
 /* char *command_line; */
 
 static const char **process_arguments (int, char **);