Profiles packages file

The packages file in profiles/ controls the packages pulled in by the @system set. The base/packages file must not be modified without discussion on the gentoo-dev list; subprofile overrides are up to the relevant arch teams.

Note that packages can be used to require that specific versions of a package be used, for example <sys-kernel/linux-headers-2.5 in a profile requiring a 2.4 kernel. If this is done with the intention of requiring only a lower version (that is to say, not a > or >= restriction, and with slots not affecting the outcome), then the entry in packages must be accompanied by a corresponding package.mask entry to ensure that no other versions get installed.