SDL 1.3 SVN and SDL_gfx Library

I installed SDL 1.3 from svn with mingw under Windows XP and it works.
Now I want to use the SDL_gfx Library, but there ist one Problem:

I found that one:
.> …
…> SDL_PixelFormat seems to be completely different. Will some
…> compatibility be added for 1.2’s SDL_PixelFormat? or will there be a
…> rough “conversion” guide made to upgrade code to 1.3? I prefer the
…> former, because I’ve never been a big fan of preprocessor #ifs in the code.
.> The SDL_PixelFormat is now used just to describe the pixel format, and has
.> all the same fields it did for that (palette, BitsPerPixel, masks, etc.).
.> The blit modifiers (colorkey, per-surface alpha) are now stored in the
.> surfaces and can be accessed with the functions in SDL_surface.h
.> …
.> -Sam Lantinga, Founder and President, Galaxy Gameworks LLC

There is ‘colorkey’ in “struct SDL_BlitInfo” and that one is in “struct
SDL_BlitMap” and that is in “struct SDL_Surface”. So I tried it like this:

From SDL_Surface src to “struct SDL_BlitMap *map” to "struct SDL_BlitInfo info"
to “Uint32 colorkey” but there comes an error:
SDL_rotozoom.c|662|error: dereferencing pointer to incomplete type|

I think it is because :
struct SDL_BlitMap *map; /**< Private */
is private and so its members are not accessible.

But which function should now be called to get the colorkey from SDL_BlitInfo?
I don’t see any in SDL_surface.h that could match.