Various improvements, including OpenBSD native audio.
* Fix audio device path. This has caused audio not to work without the
esd flavor before, many people (including me) had link to /dev/dsp because
of linux emulation programs and haven't noticed the problem.
* Fix OSS audio.
* Sync libtool patches
* Properly include @SYSTEM_LIBS@ in sdl-config to ensure proper linking
of SDL applications.
flavor, being the default one (fetching distfile from an external site).
- Isolate esd as a separate flavor from oss -- a combination with either
"sun" or "oss" is possible.