The build process of madwifi-driver uses uudecode which is part of the sharutils ebuild but app-arch/sharutils isn't listed as a dependency. I was helping a friend with a new install so I don't have emerge info or anything else but I think it was the 20040909 ebuild that was effected (probably previous ones too because the firmware (called hal I guess) is uuencoded with the source code).
Added horton and solar to CC:
Thanks for catching and reporting this Colin. I added dep of app-arch/sharutils to madwifi-driver-0.1_pre20041019.ebuild in cvs revision-1.2 mobile@ close this if you want as FIXED
Solar, please close bugs as FIXED when you've fixed them.