For those who may not know, chromium-os currently uses a hard-host-depends ebuild as a workaround for our lack of HDEPEND support [1]. We could easily add HDEPEND in EAPI 5 if we want, since we already have a Portage patch attached to bug #317337 [2]. Here is a summary of what that Portage patch will do:
In EAPI 5 or later, DEPEND has been divided into two parts: DEPEND for build-time target dependencies, and HDEPEND for build-time host dependencies. This division is designed specifically to minimize difficulty in the process of adapting ebuilds that were written for earlier EAPIs, and therefore it also minimizes the adjustments that ebuild developers will have to make to the thought processes involved when writing ebuilds from scratch. In an environment that does not involve cross-compilation, HDEPEND behaves the same as DEPEND. When an ebuild is converted from EAPI 4 or earlier to EAPI 5 or later, in order to support cross-compilation environments, some dependencies may need to be migrated to HDEPEND. For ebuilds that have EAPI 5 or later, the emerge --root-deps option has no effect since it is made obsolete by division between DEPEND and HDEPEND. If EAPI 4 or earlier ebuilds are used in combination with EAPI 5 or later ebuilds, the --root-deps behavior will still be applied to the EAPI 4 or earlier ebuilds (there is no behavior change for ebuilds having older EAPIs). [1] http://www.chromium.org/chromium-os/how-tos-and-troubleshooting/portage-build-faq [2] https://bugs.gentoo.org/show_bug.cgi?id=317337 -- Thanks, Zac
