Added a [libui] and a newline to the message printed by complain().

TODO.md

@@ -1,5 +1,3 @@
-- make sure complain()s don't have \n at the end; add one on each platform
-	- add a `[libui]` to the beginning of the message
 - figure out what to do on Windows and GTK+ if we don't have menus but the user wants a menubar (zero-height widget? don't bother? complain?)
 - bin.c
 	- find a way to consolidate the duplicate code across OSs

darwin/util.m

@@ -24,7 +24,9 @@ void complain(const char *fmt, ...)
 	va_list ap;
 
 	va_start(ap, fmt);
+	fprintf(stderr, "[libui] ");
 	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, "\n");
 	va_end(ap);
 	abort();
 }

unix/util.c

@@ -4,10 +4,10 @@
 void complain(const char *fmt, ...)
 {
 	va_list ap;
+	char *msg;
 
 	va_start(ap, fmt);
-	// there's no g_errorv() in glib 2.32, so do it manually instead
-	g_logv(G_LOG_DOMAIN, G_LOG_LEVEL_ERROR, fmt, ap);
+	msg = g_strdup_vprintf(fmt, ap);
 	va_end(ap);
-	abort();		// just in case
+	g_error("[libui] %s\n", msg);
 }

windows/util.c

@@ -78,7 +78,9 @@ void complain(const char *fmt, ...)
 	va_list ap;
 
 	va_start(ap, fmt);
+	fprintf(stderr, "[libui] ");
 	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, "\n");
 	va_end(ap);
 	abort();
 }