Based on PR 41470 by Guillaume Lasmayous.
Pkgsrc change:
* LICENSE=gnu-gpl-v2
* bump shlib major 0 => 1, (previously, just not defined),
so bump ABI_DEPENDS.libmpd.
libmpd is trying to provide a easy to use high level, callback
based access to mpd. It tries to be fast and keep the data transfer
with mpd to the minimum. To do this it implements queues for deleting
and adding songs. There is extra functionallity added for the ease
of the programmer.
