sysemu: Export 'no_shutdown'

It's a global variable already, do_quit() will use it.

Signed-off-by: Luiz Capitulino <[email protected]>
diff --git a/sysemu.h b/sysemu.h
index 48ee66c..879446a 100644
--- a/sysemu.h
+++ b/sysemu.h
@@ -128,6 +128,7 @@
 extern int cursor_hide;
 extern int graphic_rotate;
 extern int no_quit;
+extern int no_shutdown;
 extern int semihosting_enabled;
 extern int old_param;
 extern int boot_menu;