shorten compile time check for signal handler return type

Author: dterrahe

src/control/signal.c

@@ -395,7 +395,7 @@ void dt_control_signal_connect(const dt_control_signal_t *ctlsig, dt_signal_t si
 {
   _print_trace(signal, DT_DEBUG_SIGNAL_ACT_CONNECT, "connect");
 
-  g_signal_connect(G_OBJECT(ctlsig->sink), _signal_description[signal].name, G_CALLBACK(cb), user_data);
+  g_signal_connect_data(G_OBJECT(ctlsig->sink), _signal_description[signal].name, G_CALLBACK(cb), user_data, NULL, 0);
 }
 
 void dt_control_signal_disconnect(const struct dt_control_signal_t *ctlsig, GCallback cb, gpointer user_data)

src/gui/gtk.h

@@ -646,22 +646,10 @@ static inline GCallback G_CALLBACK(void *f) { return (GCallback)f; } // as a mac
 #undef _Static_assert
 #undef  g_signal_connect
 #define g_signal_connect(instance, signal, c_handler, user_data) do { \
-  _Static_assert((FALSE \
-    BOOLSIGNAL(signal, button-press-event) \
-    BOOLSIGNAL(signal, button-release-event) \
-    BOOLSIGNAL(signal, motion-notify-event) \
-    BOOLSIGNAL(signal, enter-notify-event) \
-    BOOLSIGNAL(signal, leave-notify-event) \
-    BOOLSIGNAL(signal, key-press-event) \
-    BOOLSIGNAL(signal, configure-event) \
-    BOOLSIGNAL(signal, focus-out-event) \
-    BOOLSIGNAL(signal, focus-in-event) \
-    BOOLSIGNAL(signal, scroll-event) \
-    BOOLSIGNAL(signal, delete-event) \
+  _Static_assert(((strlen(signal)>4 && !strcmp("event", &signal[strlen(signal)-5])) \
     BOOLSIGNAL(signal, drag-motion) \
     BOOLSIGNAL(signal, drag-failed) \
     BOOLSIGNAL(signal, drag-drop) \
-    BOOLSIGNAL(signal, event) \
     BOOLSIGNAL(signal, focus) \
     BOOLSIGNAL(signal, draw) \
     BOOLSIGNAL(signal, popup-menu) \