Make clients exit orderly when there is no connection

clients/dnd.c

@@ -581,6 +581,10 @@ main(int argc, char *argv[])
 	srandom(tv.tv_usec);
 
 	d = display_create(&argc, &argv, option_entries);
+	if (d == NULL) {
+		fprintf(stderr, "failed to create display: %m\n");
+		return -1;
+	}
 
 	display_set_drag_offer_handler(d, drag_offer_handler);
 

clients/flower.c

@@ -124,6 +124,10 @@ int main(int argc, char *argv[])
 	struct display *d;
 
 	d = display_create(&argc, &argv, NULL);
+	if (d == NULL) {
+		fprintf(stderr, "failed to create display: %m\n");
+		return -1;
+	}
 
 	flower.x = 512;
 	flower.y = 384;

clients/gears.c

@@ -413,6 +413,10 @@ int main(int argc, char *argv[])
 	struct gears *gears;
 
 	d = display_create(&argc, &argv, NULL);
+	if (d == NULL) {
+		fprintf(stderr, "failed to create display: %m\n");
+		return -1;
+	}
 	gears = gears_create(d);
 	display_run(d);
 

clients/image.c

@@ -244,6 +244,10 @@ main(int argc, char *argv[])
 	int i;
 
 	d = display_create(&argc, &argv, option_entries);
+	if (d == NULL) {
+		fprintf(stderr, "failed to create display: %m\n");
+		return -1;
+	}
 
 	for (i = 1; i < argc; i++) {
 		struct image *image;

clients/smoke.c

@@ -267,6 +267,10 @@ int main(int argc, char *argv[])
 	int size;
 
 	d = display_create(&argc, &argv, NULL);
+	if (d == NULL) {
+		fprintf(stderr, "failed to create display: %m\n");
+		return -1;
+	}
 
 	smoke.x = 200;
 	smoke.y = 200;

clients/terminal.c

@@ -548,6 +548,10 @@ int main(int argc, char *argv[])
 	struct terminal *terminal;
 
 	d = display_create(&argc, &argv, option_entries);
+	if (d == NULL) {
+		fprintf(stderr, "failed to create display: %m\n");
+		return -1;
+	}
 
 	terminal = terminal_create(d, option_fullscreen);
 	if (terminal_run(terminal, "/bin/bash"))

clients/view.c

@@ -207,6 +207,10 @@ main(int argc, char *argv[])
 	int i;
 
 	d = display_create(&argc, &argv, option_entries);
+	if (d == NULL) {
+		fprintf(stderr, "failed to create display: %m\n");
+		return -1;
+	}
 
 	for (i = 1; i < argc; i++) {
 		struct view *view;