System: Support saving screenshots in save states

src/core/save_state_version.h

@@ -2,4 +2,30 @@
 #include "types.h"
 
 static constexpr u32 SAVE_STATE_MAGIC = 0x43435544;
-static constexpr u32 SAVE_STATE_VERSION = 23;
+static constexpr u32 SAVE_STATE_VERSION = 24;
+
+#pragma pack(push, 4)
+struct SAVE_STATE_HEADER
+{
+  enum : u32
+  {
+    MAX_TITLE_LENGTH = 128,
+    MAX_GAME_CODE_LENGTH = 32
+  };
+
+  u32 magic;
+  u32 version;
+  char title[MAX_TITLE_LENGTH];
+  char game_code[MAX_GAME_CODE_LENGTH];
+  
+  u32 screenshot_width;
+  u32 screenshot_height;
+  u32 screenshot_size;
+  u32 offset_to_screenshot;
+
+  u32 data_compression_type;
+  u32 data_compressed_size;
+  u32 data_uncompressed_size;
+  u32 offset_to_data;
+};
+#pragma pack(pop)