Patched to compile on Windows.

src/video/wincommon/SDL_lowvideo.h

@@ -141,7 +141,7 @@ extern void DX5_SoundFocus(HWND window);
 LRESULT CALLBACK WinMessage(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
 
 /* JFP: Implementation of ToUnicode() that works on 9x/ME/2K/XP */
-typedef int (WINAPI *ToUnicodeFN)(UINT, UINT, PBYTE, LPWSTR, int, UINT);
+typedef int (WINAPI *ToUnicodeFN)(UINT, UINT, const BYTE *, LPWSTR, int, UINT);
 
 extern ToUnicodeFN SDL_ToUnicode;
 

src/video/wincommon/SDL_sysevents.c

@@ -816,7 +816,7 @@ static int GetCodePage()
 	return cp;
 }
 
-static int WINAPI ToUnicode9xME(UINT vkey, UINT scancode, const PBYTE keystate, LPWSTR wchars, int wsize, UINT flags)
+static int WINAPI ToUnicode9xME(UINT vkey, UINT scancode, const BYTE *keystate, LPWSTR wchars, int wsize, UINT flags)
 {
 	BYTE	chars[2];