The sources of OM 5.2.1 have been released in oct. 2007.
This package contains the whole OpenMusic kernel and main projects sources, as well as the API code for compiling OM on SBCL/GTK (Linux), Allegro CL (Windows XP), or MCL (MacOSX PPC).
For compilation instructions, see the OM website at http://recherche.ircam.fr/equipes/repmus/OpenMusic (Windows, Macintosh) and the readme file include in the source release (Linux).
OpenMusic V (for Linux) will soon be available here in cvs. We will have to completely rearrange the structure of all files found here. The 4.7 version is completely obsolete. since OpenMusic has been cleaned up and uses now SBCL lisp compiler and Clg-gtk+ bindings for the Linux version. You will soon have fresh news here.