util: Implement meta_topic() using g_message()

This will get us things like timestamps.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2094>

src/core/util.c

@@ -274,8 +274,8 @@ meta_verbose_real (const char *format, ...)
   va_end (args);
 }
 
-static const char*
-topic_name (MetaDebugTopic topic)
+const char *
+meta_topic_to_string (MetaDebugTopic topic)
 {
   switch (topic)
     {
@@ -369,7 +369,7 @@ meta_topic_real_valist (MetaDebugTopic topic,
 
   out = logfile ? logfile : stderr;
 
-  fprintf (out, "%s: ", topic_name (topic));
+  fprintf (out, "%s: ", meta_topic_to_string (topic));
 
   if (topic == META_DEBUG_SYNC)
     {

src/meta/util.h

@@ -177,6 +177,8 @@ GPid meta_show_dialog (const char *type,
 /* To disable verbose mode, we make these functions into no-ops */
 #ifdef WITH_VERBOSE_MODE
 
+const char * meta_topic_to_string (MetaDebugTopic topic);
+
 #define meta_verbose(...) \
   G_STMT_START \
     { \
@@ -185,11 +187,13 @@ GPid meta_show_dialog (const char *type,
     } \
   G_STMT_END
 
-#define meta_topic(debug_topic,...) \
+#define meta_topic(debug_topic, ...) \
   G_STMT_START \
     { \
       if (meta_is_topic_enabled (debug_topic)) \
-        meta_topic_real (debug_topic, __VA_ARGS__); \
+        { \
+          g_message (__VA_ARGS__); \
+        } \
     } \
   G_STMT_END