Removed atexit() from most of the test programs; atexit(SDL_Quit) isn't safe if SDL is built with a non-cdecl calling convention, and it's just generally bad practice anyhow. Now programs explicitly call SDL_Quit() where appropriate, wrap SDL_Quit() in a cdecl function where it can't be avoided, and rely on the parachute where a crash might have hit the atexit() before (these ARE test programs, after all!).

## Makefile.am for SDL using the XBIOS video driver

noinst_LTLIBRARIES = libvideo_xbios.la
libvideo_xbios_la_SOURCES = $(XBIOS_SRCS)

# The SDL XBIOS video driver sources
XBIOS_SRCS = 	\
	SDL_xbios.c	\
	SDL_xbios.h	\
	SDL_xbios_blowup.c	\
	SDL_xbios_blowup.h	\
	SDL_xbios_centscreen.c	\
	SDL_xbios_centscreen.h	\
	SDL_xbios_sb3.c	\
	SDL_xbios_sb3.h