gtk: a dead key hands the pending text back first

GtkIMContextSimple composes dead keys, and while it did the daemon still
held the syllable typed before them: the composed é was inserted first
and 하 reappeared after it.  A key the daemon does not take now resets
the composition when Simple begins composing on it — a modifier press,
which is also no key, leaves it alone.

gtk/main.c

@@ -252,6 +252,7 @@ kpress(GtkIMContext *ctx, GdkEventKey *ev)
 	char pre[Ipcfieldmax+1];
 	uint32_t key, mod;
 	Ipcresp resp;
+	gboolean r;
 
 	im = (Im*)ctx;
 	if(ev->type != GDK_KEY_PRESS){
@@ -263,8 +264,13 @@ kpress(GtkIMContext *ctx, GdkEventKey *ev)
 		return simplefilter(ctx, ev, 0);
 	key = ipckeysym(ev->keyval, gdk_keyval_to_unicode(ev->keyval));
 	mod = ipcmod(ev->state);
-	if(im->private || key == 0)
-		return simplefilter(ctx, ev, 0);
+	if(im->private || key == 0){
+		r = simplefilter(ctx, ev, 0);
+		/* A dead key starts a compose: pending text was typed first. */
+		if(im->simpleactive)
+			sendreset(im);
+		return r;
+	}
 	if(srvconnect(im) < 0)
 		return simplefilter(ctx, ev, 0);
 	/* A retained GDK window may have moved since the last cursor report. */