Fixed borked font bitmap allocation size

gui/gui.c

@@ -3847,8 +3847,10 @@ int main(void)
 	struct File_Read_Result font_data = read_file__cruddy(font_file);
 	// TODO(Zelaven): How much data do I have to make sure that I read at minimum?
 	assert(font_data.size > 16);
-	g_font_bitmap = memory_arena_allocate(&font_arena, sizeof(char), _Alignof(char));
 	{
+		int font_bitmap_size = g_font_bitmap_width * g_font_bitmap_height;
+		g_font_bitmap = memory_arena_allocate(
+			&font_arena, font_bitmap_size, _Alignof(char));
 		int bake_font_return_value = stbtt_BakeFontBitmap(
 			font_data.data, 0,
 			20.0,