Quartz driver OpenGL updates: Driver can now open whatever library is specified in SDL_GL_LoadLibrary() call (previously, it ignored this parameter), and uses the default system library when NULL is specified. Also, library is loaded once in SDL_GL_LoadLibrary() and not every call to SDL_GL_GetProcAddress().

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

noinst_LTLIBRARIES = libvideo_picogui.la
libvideo_picogui_la_SOURCES = $(PICOGUI_SRCS)

# The SDL PicoGUI video driver sources
PICOGUI_SRCS = 			\
	SDL_pgevents.c		\
	SDL_pgevents_c.h	\
	SDL_pgvideo.c		\
	SDL_pgvideo.h