SDL_CDOpen() fails on Linux if data track on disc is mounted in the filesystem. Removing O_EXCL from open() call fixes this. Problem and solution noted by "Fosters": http://www.libsdl.org/pipermail/sdl/2005-March/068028.html

## Makefile.am for SDL using the Network Audio System sound driver

noinst_LTLIBRARIES = libaudio_nas.la
libaudio_nas_la_SOURCES = $(SRCS)

# The SDL audio driver sources
SRCS =	SDL_nasaudio.c	\
	SDL_nasaudio.h