Complex sentence: The official development of mpg123 and its library, mpglib, had ceased for several years, and as some serious security holes emerged, patches were submitted by third party developers for the Debian and Gentoo Linux packages, as well as the FreeBSD ports collection.
Split into simpler sentences: The official development of the mpg123 software had ceased for several years and there accumulated some serious security holes that were only fixed by third party developers. Notable changes have been available in the Debian and Gentoo Linux packages, as well as the FreeBSD ports collection.