examples: fix warnings about 0 assignments to reference fields (#21133)

examples/flappylearning/game.v

@@ -172,9 +172,7 @@ fn (mut app App) update() {
 }
 
 fn main() {
-	mut app := &App{
+	mut app := &App{}
-		gg: 0
-	}
 	mut font_path := os.resource_abs_path(os.join_path('..', 'assets', 'fonts', 'RobotoMono-Regular.ttf'))
 	$if android {
 		font_path = 'fonts/RobotoMono-Regular.ttf'

examples/game_of_life/life_gg.v

@@ -37,7 +37,6 @@ fn frame(mut app App) {
 
 fn main() {
 	mut app := App{
-		gg: 0
 		a: automaton.gun()
 	}
 	app.gg = gg.new_context(

examples/gg/drag_n_drop.v

@@ -17,9 +17,7 @@ mut:
 
 fn main() {
 	mut font_path := os.resource_abs_path(os.join_path('..', 'assets', 'fonts', 'RobotoMono-Regular.ttf'))
-	mut app := &App{
+	mut app := &App{}
-		gg: 0
-	}
 	app.gg = gg.new_context(
 		bg_color: gx.rgb(174, 198, 255)
 		width: 600

examples/gg/draw_pixels.v

@@ -25,7 +25,6 @@ fn main() {
 		}
 	}
 	mut app := &App{
-		gg: 0
 		pixels: pixels
 	}
 	app.gg = gg.new_context(

examples/gg/raven_text_rendering.v

@@ -61,9 +61,7 @@ mut:
 }
 
 fn main() {
-	mut app := &App{
+	mut app := &App{}
-		gg: 0
-	}
 	mut font_path := os.resource_abs_path(os.join_path('..', 'assets', 'fonts', 'RobotoMono-Regular.ttf'))
 	$if android {
 		font_path = 'fonts/RobotoMono-Regular.ttf'

examples/gg/rectangles.v

@@ -14,9 +14,7 @@ mut:
 }
 
 fn main() {
-	mut app := &App{
+	mut app := &App{}
-		gg: 0
-	}
 	app.gg = gg.new_context(
 		bg_color: gx.white
 		width: win_width

examples/gg/stars.v

@@ -43,7 +43,6 @@ mut:
 
 fn main() {
 	mut app := &App{
-		gg: 0
 		stars: []Star{len: max_stars}
 		v_letters: []VLetter{len: max_v_letters}
 	}

examples/gg/worker_thread.v

@@ -22,9 +22,7 @@ mut:
 }
 
 fn main() {
-	mut app := &App{
+	mut app := &App{}
-		gg: 0
-	}
 	app.gg = gg.new_context(
 		width: win_width
 		height: win_height

examples/hot_reload/graph.v

@@ -14,9 +14,7 @@ mut:
 }
 
 fn main() {
-	mut context := &Context{
+	mut context := &Context{}
-		gg: 0
-	}
 	context.gg = gg.new_context(
 		width: size
 		height: size

examples/snek/snek.v

@@ -195,9 +195,7 @@ const font = $embed_file('../assets/fonts/RobotoMono-Regular.ttf')
 
 // setup
 fn main() {
-	mut app := App{
+	mut app := App{}
-		gg: 0
-	}
 	app.reset_game()
 	app.best.load()
 

examples/sokol/sounds/melody.v

@@ -33,9 +33,7 @@ fn my_audio_stream_callback(buffer &f32, num_frames int, num_channels int, mut a
 
 fn main() {
 	println(credits)
-	mut state := &AppState{
+	mut state := &AppState{}
-		gg: 0
-	}
 	audio.setup(
 		stream_userdata_cb: my_audio_stream_callback
 		user_data: state

examples/ttf_font/example_ttf.v

@@ -115,9 +115,7 @@ fn my_event_manager(mut ev gg.Event, mut app App_data) {
 }
 
 fn main() {
-	mut app := &App_data{
+	mut app := &App_data{}
-		gg: 0
-	}
 	app.gg = gg.new_context(
 		width: win_width
 		height: win_height