win-capture: Wait before auto-fullscreen hooking

If using the auto-fullscreen feature to hook in to a fullscreen, I found
that if you don't wait a few seconds before initializing the hook that
you can catch the process when it's just starting up and loading
important libraries (especially things such as steam/uplay/etc), which
can cause a little bit of interference with the process and on rare
occasions cause it to crash.

To help prevent the likelihood of that happening, this just makes it so
that the hook waits at least 3 seconds before even attempting to inject
the hook when using auto-fullscreen mode.  After some extensive testing
I haven't had any issues since.

plugins/win-capture/game-capture.c

@@ -78,6 +78,7 @@ struct game_capture {
 	float                         retry_time;
 	float                         fps_reset_time;
 	float                         retry_interval;
+	bool                          wait_for_target_startup : 1;
 	bool                          active : 1;
 	bool                          capturing : 1;
 	bool                          activate_hook : 1;
@@ -196,6 +197,7 @@ static void stop_capture(struct game_capture *gc)
 	}
 
 	gc->copy_texture = NULL;
+	gc->wait_for_target_startup = false;
 	gc->active = false;
 	gc->capturing = false;
 }
@@ -691,7 +693,20 @@ static void get_fullscreen_window(struct game_capture *gc)
 	    rect.right  == mi.rcMonitor.right  &&
 	    rect.bottom == mi.rcMonitor.bottom &&
 	    rect.top    == mi.rcMonitor.top) {
-		gc->next_window = window;
+
+		/* always wait a bit for the target process to start up before
+		 * starting the hook process; sometimes they have important
+		 * modules to load first or other hooks (such as steam) need a
+		 * little bit of time to load.  ultimately this helps prevent
+		 * crashes */
+		if (gc->wait_for_target_startup) {
+			gc->retry_interval = 3.0f;
+			gc->wait_for_target_startup = false;
+		} else {
+			gc->next_window = window;
+		}
+	} else {
+		gc->wait_for_target_startup = true;
 	}
 }