The musepack audio codec has not been actively developed in many years.
This port is kept as a convenience for users who have *.mpc files in 
their collections and want to crop them, decode them, or play them in 
apps (like moc) which do not bundle a copy of the libraries.

The encoder tool (mpcenc) has not kept up with changes in glibc, and
therefore would be broken if built on CRUX 3.7. But the statically-linked
binary available upstream (built against an older glibc) should still
work, if encoding from lossless to *.mpc is what you want to do.

Also available on the musepack project site are two optional libraries:
libreplaygain and libcuefile. If you install them before this port (under
the standard prefix /usr), then the targets mpcchap and mpcgain should 
also appear in your package.