qmp/hmp: disable screendump if PIXMAN is missing

The command requires color conversion and line-by-line feeding. We could
have a simple fallback for simple formats though.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>

ui/ui-hmp-cmds.c

@@ -437,6 +437,7 @@ void sendkey_completion(ReadLineState *rs, int nb_args, const char *str)
     }
 }
 
+#ifdef CONFIG_PIXMAN
 void coroutine_fn
 hmp_screendump(Monitor *mon, const QDict *qdict)
 {
@@ -458,6 +459,7 @@ hmp_screendump(Monitor *mon, const QDict *qdict)
 end:
     hmp_handle_error(mon, err);
 }
+#endif
 
 void hmp_client_migrate_info(Monitor *mon, const QDict *qdict)
 {

ui/ui-qmp-cmds.c

@@ -212,6 +212,7 @@ void qmp_client_migrate_info(const char *protocol, const char *hostname,
     error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "protocol", "'spice'");
 }
 
+#ifdef CONFIG_PIXMAN
 #ifdef CONFIG_PNG
 /**
  * png_save: Take a screenshot as PNG
@@ -391,3 +392,4 @@ qmp_screendump(const char *filename, const char *device,
         }
     }
 }
+#endif /* CONFIG_PIXMAN */