#243 Introduce compile-time options to support WebOS SDL

[timfelgentreff]

The version of SDL shipped on the Palm Pre does not support SDL_CDROM and does not work correctly with SDL_HWSURFACE. I have prepared two patches (https://github.com/timfel/dosbox-svn/commit/7ae7b7db7a75e751496a0c34a26ec14eac6340d6 and https://github.com/timfel/dosbox-svn/commit/8c8c07b92c5c2b77788e4e747b9abb15f0f170a8). One adds a configure switch to disable the use of the SDL_CDROM flag at initialization, the other adds a configure switch to override uses of SDL_HWSURFACE with SDL_SWSURFACE. Would be glad if support for WebOS got into mainline.