[gentoo-alt] eprefixify_patch

[Gregory M. Turner]

Current prefix SOP is to epatch a bunch of files with @GENTOO_PORTAGE_EPREFIX@ and then eprefixify the affected files.  Although this adds a bit of precision and flexibility, it leads to laundry lists in the ebuild, especially if/when we start getting more rigorous about prefixification.  The attached eclass provides eprefixify_patch, which simply prefixifies the patch itself before applying.

It also includes some quick & dirty tools to prefixify /bin/{ba,}sh shebangs.  I'm using both in my overlay.  So far, so good.  What I'm using it /for/ is a more interesting question that I'd like to bring up in a separate, presumably more controversial thread.  Anyhow, for the moment I thought these might come in handy or at least precipitate an interesting flamewar :)

-gmt