libpac is a library written in C to decode SBStudio PAC modules into a stream of PCM audio data. SBStudio is a music tracker for MS-DOS written by Henning Hellstroem in the early 1990s.
libpac is not a player in itself since there's no code to actually write the decoded audio data anywhere. It was designed to be used by plugins, e.g. for the X MultiMedia System (XMMS), that have their own output code.
The code should compile successfully on any ISO C (C99) compliant compiler. If not, please let me know. See Bugs.