Dynamically load X11 libraries like we currently do for alsa, esd, etc. This allows you to run an SDL program on a system without Xlib, since it'll just report the x11 target unavailable at runtime.

## Makefile.am for the osf cdrom driver for SDL

noinst_LTLIBRARIES = libcdrom_osf.la
libcdrom_osf_la_SOURCES = $(SRCS)

# The SDL cdrom driver sources
SRCS =  SDL_syscdrom.c