made savestate loads less fragile by adding some markers and rolling back on a mismatch.

This should make it so if you try to load an incompatible save, it simply doesn't load, instead of crashing dolphin. (I can't guarantee no crash but it's much less likely now)

Source/Core/Common/Src/ChunkFile.h

@@ -170,6 +170,17 @@ public:
 		// TODO
 		PanicAlert("Do(linked list<>) does not yet work.");
 	}
+
+	void DoMarker(const char* prevName, u32 arbitraryNumber=0x42)
+	{
+		u32 cookie = arbitraryNumber;
+		Do(cookie);
+		if(mode == PointerWrap::MODE_READ && cookie != arbitraryNumber)
+		{
+			PanicAlertT("Error: After \"%s\", found %d (0x%X) instead of save marker %d (0x%X). Aborting savestate load...", prevName, cookie, cookie, arbitraryNumber, arbitraryNumber);
+			mode = PointerWrap::MODE_MEASURE;
+		}
+	}
 };