Since gquilt v0.18 also supports Mercurial's mq managed patches as a backend. A patch to support hg as dependency is attached, not much else to say :) Thanks, James
Created attachment 133956 [details, diff] gquilt-allow_hg.patch
+ 06 Nov 2012; Kacper Kowalik <xarthisius@gentoo.org> gquilt-0.25.ebuild: + Add mercurial as alternative to quilt. Fixes bug 196523 by James Rowe + <jnrowe@gmail.com>