Also build launcher with -std=c11

Fixes #8642

kitty/launcher/cmdline.c

@@ -5,6 +5,7 @@
  * Distributed under terms of the GPL3 license.
  */
 
+#define _POSIX_C_SOURCE 200809L
 #include "shlex.h"
 #include "utils.h"
 #include "launcher.h"

kitty/launcher/utils.h

@@ -17,6 +17,7 @@
 #include <errno.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <limits.h>
 
 
 static const char* home = NULL;