Enable support for clang builds
Index: b/spectool_curses.c
===================================================================
--- a/spectool_curses.c
+++ b/spectool_curses.c
@@ -90,7 +90,7 @@
 
 		if (o == 'h') {
 			Usage();
-			return;
+			return 0;
 		} else if (o == 'n') {
 			neturl = strdup(optarg);
 			continue;
@@ -98,20 +98,20 @@
 			if (sscanf(optarg, "%d", &range) != 1) {
 				printf("Expected number for range, see listing for supported ranges\n");
 				Usage();
-				return;
+				return -1;
 			}
 			continue;
 		} else if (o == 'd') {
 			if (sscanf(optarg, "%d", &device) != 1) {
 				printf("Expected number for device, see listing for detected devices\n");
 				Usage();
-				return;
+				return -1;
 			}
 
 			if (device < 0 || device >= ndev) {
 				printf("Device number invalid, see listing for detected devices\n");
 				Usage();
-				return;
+				return -1;
 			}
 
 			continue;
Index: b/spectool_gtk.c
===================================================================
--- a/spectool_gtk.c
+++ b/spectool_gtk.c
@@ -182,7 +182,7 @@
 	GtkWidget *menu;
 	nb_aux *nbaux = (nb_aux *) aux;
 
-	g_return_if_fail(aux != NULL);
+	g_return_val_if_fail(aux != NULL, FALSE);
 
 	if (event->type == GDK_BUTTON_PRESS) {
 		GdkEventButton *bevent = (GdkEventButton *) event;
Index: b/spectool_gtk_channel.c
===================================================================
--- a/spectool_gtk_channel.c
+++ b/spectool_gtk_channel.c
@@ -43,8 +43,8 @@
 	int dbm, maxy, nchannels;
 	SpectoolWidget *wwidget;
 
-	g_return_if_fail(cwidget != NULL);
-	g_return_if_fail(IS_SPECTOOL_WIDGET(cwidget));
+	g_return_val_if_fail(cwidget != NULL, -1);
+	g_return_val_if_fail(IS_SPECTOOL_WIDGET(cwidget), -1);
 	wwidget = SPECTOOL_WIDGET(cwidget);
 
 	/* Only compute if we know a chanset and if we're inside the bounding
@@ -224,17 +224,17 @@
 	int ch;
 	GList *upd_iter;
 
-	g_return_if_fail(aux != NULL);
-	g_return_if_fail(IS_SPECTOOL_CHANNEL(aux));
-	g_return_if_fail(IS_SPECTOOL_WIDGET(aux));
+	g_return_val_if_fail(aux != NULL, FALSE);
+	g_return_val_if_fail(IS_SPECTOOL_CHANNEL(aux), FALSE);
+	g_return_val_if_fail(IS_SPECTOOL_WIDGET(aux), FALSE);
 
 	channel = SPECTOOL_CHANNEL(aux);
 	wwidget = SPECTOOL_WIDGET(aux);
 
-	g_return_if_fail(wwidget->chanopts != NULL);
-	g_return_if_fail(wwidget->chanopts->chanset != NULL);
-	g_return_if_fail(wwidget->sweepcache != NULL);
-	g_return_if_fail(wwidget->sweepcache->latest != NULL);
+	g_return_val_if_fail(wwidget->chanopts != NULL, FALSE);
+	g_return_val_if_fail(wwidget->chanopts->chanset != NULL, FALSE);
+	g_return_val_if_fail(wwidget->sweepcache != NULL, FALSE);
+	g_return_val_if_fail(wwidget->sweepcache->latest != NULL, FALSE);
 
 	if (event->button != 1)
 		return TRUE;
@@ -278,15 +278,15 @@
 	SpectoolWidget *wwidget;
 	GList *upd_iter;
 
-	g_return_if_fail(aux != NULL);
-	g_return_if_fail(IS_SPECTOOL_CHANNEL(aux));
-	g_return_if_fail(IS_SPECTOOL_WIDGET(aux));
+	g_return_val_if_fail(aux != NULL, FALSE);
+	g_return_val_if_fail(IS_SPECTOOL_CHANNEL(aux), FALSE);
+	g_return_val_if_fail(IS_SPECTOOL_WIDGET(aux), FALSE);
 
 	channel = SPECTOOL_CHANNEL(aux);
 	wwidget = SPECTOOL_WIDGET(aux);
 
-	g_return_if_fail(wwidget->sweepcache != NULL);
-	g_return_if_fail(wwidget->sweepcache->latest != NULL);
+	g_return_val_if_fail(wwidget->sweepcache != NULL, FALSE);
+	g_return_val_if_fail(wwidget->sweepcache->latest != NULL, FALSE);
 
 	if (event->is_hint) {
 		gdk_window_get_pointer(event->window, &x, &y, &state);
@@ -298,8 +298,8 @@
 
 	/* Search for the channel positions, update the graph if we've changed
 	 * the highlighted channel */
-	g_return_if_fail(wwidget->chanopts != NULL);
-	g_return_if_fail(wwidget->chanopts->chanset != NULL);
+	g_return_val_if_fail(wwidget->chanopts != NULL, FALSE);
+	g_return_val_if_fail(wwidget->chanopts->chanset != NULL, FALSE);
 
 	if ((ch = spectool_channel_find_chan_pt(channel, x, y)) >= -1) {
 		if (ch != wwidget->chanopts->hi_chan) {
Index: b/spectool_gtk_hw_registry.c
===================================================================
--- a/spectool_gtk_hw_registry.c
+++ b/spectool_gtk_hw_registry.c
@@ -326,10 +326,10 @@
 
 spectool_phy *wdr_get_phy(spectool_device_registry *wdr, int slot) {
 	if (slot < 0 || slot > wdr->max_dev)
-		return;
+		return NULL;
 
 	if (wdr->devices[slot] == NULL)
-		return;
+		return NULL;
 
 	return wdr->devices[slot]->phydev;
 }
@@ -523,10 +523,10 @@
 	char err[SPECTOOL_ERROR_MAX];
 
 	if (wdrpr->slot < 0 || wdrpr->slot > wdrpr->wdr->max_dev)
-		return;
+		return FALSE;
 
 	if (wdrpr->wdr->netservers[wdrpr->slot] == NULL)
-		return;
+		return FALSE;
 
 	sr = wdrpr->wdr->netservers[wdrpr->slot]->srv;
 
@@ -537,7 +537,7 @@
 			Spectool_Alert_Dialog(err);
 
 			wdr_close_net(wdrpr->wdr, wdrpr->slot);
-			return;
+			return TRUE;
 		}
 
 	} while ((r & SPECTOOL_NETCLI_POLL_ADDITIONAL));
Index: b/spectool_gtk_planar.c
===================================================================
--- a/spectool_gtk_planar.c
+++ b/spectool_gtk_planar.c
@@ -351,15 +351,15 @@
 	SpectoolWidget *wwidget;
 	int ch;
 
-	g_return_if_fail(aux != NULL);
-	g_return_if_fail(IS_SPECTOOL_PLANAR(aux));
-	g_return_if_fail(IS_SPECTOOL_WIDGET(aux));
+	g_return_val_if_fail(aux != NULL, FALSE);
+	g_return_val_if_fail(IS_SPECTOOL_PLANAR(aux), FALSE);
+	g_return_val_if_fail(IS_SPECTOOL_WIDGET(aux), FALSE);
 
 	planar = SPECTOOL_PLANAR(aux);
 	wwidget = SPECTOOL_WIDGET(aux);
 
-	g_return_if_fail(wwidget->sweepcache != NULL);
-	g_return_if_fail(wwidget->sweepcache->avg != NULL);
+	g_return_val_if_fail(wwidget->sweepcache != NULL, FALSE);
+	g_return_val_if_fail(wwidget->sweepcache->avg != NULL, FALSE);
 
 	if (event->button != 1)
 		return TRUE;
@@ -379,15 +379,15 @@
 	SpectoolPlanar *planar;
 	SpectoolWidget *wwidget;
 
-	g_return_if_fail(aux != NULL);
-	g_return_if_fail(IS_SPECTOOL_PLANAR(aux));
-	g_return_if_fail(IS_SPECTOOL_WIDGET(aux));
+	g_return_val_if_fail(aux != NULL, FALSE);
+	g_return_val_if_fail(IS_SPECTOOL_PLANAR(aux), FALSE);
+	g_return_val_if_fail(IS_SPECTOOL_WIDGET(aux), FALSE);
 
 	planar = SPECTOOL_PLANAR(aux);
 	wwidget = SPECTOOL_WIDGET(aux);
 
-	g_return_if_fail(wwidget->sweepcache != NULL);
-	g_return_if_fail(wwidget->sweepcache->avg != NULL);
+	g_return_val_if_fail(wwidget->sweepcache != NULL, FALSE);
+	g_return_val_if_fail(wwidget->sweepcache->avg != NULL, FALSE);
 
 	if (event->is_hint) {
 		gdk_window_get_pointer(event->window, &x, &y, &state);
Index: b/spectool_gtk_spectral.c
===================================================================
--- a/spectool_gtk_spectral.c
+++ b/spectool_gtk_spectral.c
@@ -415,9 +415,9 @@
 	cairo_pattern_t *pattern;
 	int cp;
 
-	g_return_if_fail(widget != NULL);
-	g_return_if_fail(aux != NULL);
-	g_return_if_fail(IS_SPECTOOL_SPECTRAL(aux));
+	g_return_val_if_fail(widget != NULL, FALSE);
+	g_return_val_if_fail(aux != NULL, FALSE);
+	g_return_val_if_fail(IS_SPECTOOL_SPECTRAL(aux), FALSE);
 
 	spectral = SPECTOOL_SPECTRAL(aux);
 
Index: b/spectool_gtk_topo.c
===================================================================
--- a/spectool_gtk_topo.c
+++ b/spectool_gtk_topo.c
@@ -408,9 +408,9 @@
 	cairo_pattern_t *pattern;
 	int cp;
 
-	g_return_if_fail(widget != NULL);
-	g_return_if_fail(aux != NULL);
-	g_return_if_fail(IS_SPECTOOL_TOPO(aux));
+	g_return_val_if_fail(widget != NULL, FALSE);
+	g_return_val_if_fail(aux != NULL, FALSE);
+	g_return_val_if_fail(IS_SPECTOOL_TOPO(aux), FALSE);
 
 	topo = SPECTOOL_TOPO(aux);
 
Index: b/spectool_gtk_widget.c
===================================================================
--- a/spectool_gtk_widget.c
+++ b/spectool_gtk_widget.c
@@ -190,8 +190,8 @@
 	SpectoolWidgetController *con = (SpectoolWidgetController *) widget;
 	char alt_title_text[32];
 
-	g_return_if_fail(widget != NULL);
-	g_return_if_fail(event != NULL);
+	g_return_val_if_fail(widget != NULL, FALSE);
+	g_return_val_if_fail(event != NULL, FALSE);
 
 	if (event->type == GDK_BUTTON_PRESS) {
 		GdkEventButton *bevent = (GdkEventButton *) event;
@@ -237,8 +237,8 @@
 	GdkColor c;
 	GtkStyle *style;
 
-	g_return_if_fail(widget != NULL);
-	g_return_if_fail(IS_SPECTOOL_WIDGET(widget));
+	g_return_val_if_fail(widget != NULL, NULL);
+	g_return_val_if_fail(IS_SPECTOOL_WIDGET(widget), NULL);
 
 	wwidget = SPECTOOL_WIDGET(widget);
 
@@ -300,9 +300,9 @@
 	GtkWidget *menu;
 	GdkEvent *event = (GdkEvent *) button;
 
-	g_return_if_fail(widget != NULL);
-	g_return_if_fail(aux != NULL);
-	g_return_if_fail(IS_SPECTOOL_WIDGET(aux));
+	g_return_val_if_fail(widget != NULL, 0);
+	g_return_val_if_fail(aux != NULL, 0);
+	g_return_val_if_fail(IS_SPECTOOL_WIDGET(aux), 0);
 
 	wwidget = SPECTOOL_WIDGET(aux);
 
@@ -786,8 +786,8 @@
 	SpectoolWidget *wwidget;
 	cairo_t *cr;
 
-	g_return_if_fail(widget != NULL);
-	g_return_if_fail(IS_SPECTOOL_WIDGET(aux));
+	g_return_val_if_fail(widget != NULL, TRUE);
+	g_return_val_if_fail(IS_SPECTOOL_WIDGET(aux), TRUE);
 	wwidget = SPECTOOL_WIDGET(aux);
 
 	cr = gdk_cairo_create(widget->window);
Index: b/spectool_raw.c
===================================================================
--- a/spectool_raw.c
+++ b/spectool_raw.c
@@ -101,7 +101,7 @@
 
 		if (o == 'h') {
 			Usage();
-			return;
+			return 0;
 		} else if (o == 'b') {
 			bcastlisten = 1;
 		} else if (o == 'n') {
