Support --debug option for GNU/Linux emulation.

ChangeLog

@@ -1,3 +1,8 @@
+2017-10-10  NIIBE Yutaka  <gniibe@fsij.org>
+
+	* src/main.c (main): Support --debug option.
+	* chopstx: Update to 1.5.
+
 2017-10-06  NIIBE Yutaka  <gniibe@fsij.org>
 
 	* src/configure (flash_override): Fix suggested by Jeremy Drake.

src/main.c

@@ -240,6 +240,13 @@ main (int argc, const char *argv[])
       exit (0);
     }
 
+  if (argc >= 2 && !strncmp (argv[1], "--debug=", 8))
+    {
+      debug = strtol (&argv[1][8], NULL, 10);
+      argc--;
+      argv++;
+    }
+
   if (argc >= 2 && !strncmp (argv[1], "--vidpid=", 9))
     {
       extern uint8_t device_desc[];