Created a gentoo overlay. Right now it only has ebuilds for gitphp. You can set it up by doing something like:
git clone http://www.xiphux.com/git/gentoo.git /usr/local/portage/xiphux
And adding to your make.conf:
PORTDIR_OVERLAY="/usr/local/portage/xiphux"
The ebuild will handle changing the permissions of templates_c and will copy gitphp.conf.php.example to gitphp.conf.php, and will allow you to merge changes to gitphp.conf.php using etc-update when you upgrade.
Unfortunately, I don’t know of a good way to make webapp-config handle the templates_c directory, so when you unmerge the package you have to get rid of the templates_c directory manually (since by then the webserver has generated the compiled files in there, so webapp-config won’t remove it since it’s not empty).

GitPHP 0.0.7
This one is a minor release. No new config options.
There are three small(-ish) changes:
I wouldn’t normally do a release this small, but I’m planning on making some major changes to the way templates work (internally, not really much difference visible to users), which is a change that could potentially take a while, so I wanted to get these fixes out and released before I started anything.
As always, packages are available from the GitPHP page, and bugs can be reported by Mantis.