New update of the Sega Dreamcast emulator for Linux.
Changelog:
* Fix configure script to abort if it doesn’t find a required library (eg, libGL.so or
libz.so)
* Add checks to the configure script for linux/cdrom.h, and avoid building the
CD-Rom driver if it’s not found.
* Add preliminary support for nulldc-style gdi images
* Implement gdrom mode select command (mostly stub)
* Fix some non-64bit-safe code
* Fix the maple 0×00000700 issue
