xmp: Update to 4.1.0

Switch to native audio drivers for NetBSD and Solaris, which it has,
somehow.

4.1.0 (20160719):
- Requires libxmp 4.4
- Add option to force tracker emulation
- Add option to use simulated Amiga mixers
- Add option to set the maximum number of virtual channels
- Add command to switch between standard and classic mixers
- Add command to display current mixer type
- Fix default amplification factor
- Fix module-specific configuration file options
- Fix screen corruption when module uses more than 255 virtual
  channels (reported by Lionel Debroux)
- Remove option --offset-bug-emulation

4.0.11 (20160306):
- Mark surround channels in channel list
- Address errors reported by Coverity Scan

(nia)