AdvanceCOMP is a set of three utilities: advdef, advpng, advmng and advzip. It will recompress png, mng and zip-files using the Deflate 7-Zip implementation, which is on average about 3% better than "zip -9". It will make your complete MAME ROM-collection 200-300 MB smaller. :)
Created attachment 13586 [details] app-arch/advancecomp/advancecomp-1.6.ebuild
Cool, Assigning to me....
committed as app-arch/advancecomp-1.8, thanks! I made a quick patch to get bzip2 support to compile, the ChangeLog reads: 31 Oct 2003; Tavis Ormandy <taviso@gentoo.org> advancecomp-1.8.ebuild, files/advancecomp-bzip2-compile-plz-k-thx.diff: Initial import, thanks to Per Wigren <wigren@home.se> for providing the ebuild this was based on in #23158