Donnie already written quite a lot about porting applications yet to be ported to modular X, but there is something that is probably difficult for many people to see as a problem.
Porting applications that usually inherits X11 dependency from other libraries.
KDE is a big example of that: most of it uses Qt abstractions instead of accessing X11 directly, so after Qt is ported there was no need to port all KDE packages. Unfortunately this isn’t always the case.
When I started dropping support for things like xcomposite and xscreensaver, I added a few dependencies for Modular X to some packages like kdesktop and kwin, but probably many are still missing.
Today I fixed net-im/kopete to have a xscreensaver useflag to enable idle detection, as I added RSIBreak to the tree with libXScrnSaver as an hard dependency, and then I found that it was linking to lot more stuff… I had to rebuild Kopete 4 times today then, and that quite sucks because it takes a lot of time to build 🙁 I should probably ask Matt if it’s possible to add a few –disable parameter to configure so one has not to build things like the latex plugin, all the protocols like gadugadu and so on, trying to minimise both the build time and the stuff that can break (remember: more code, more stuff that can break).
This is what I like of Gentoo mainly. I can choose what I want and what I do not want to compile. Not even use, compile. The less libraries I link against, the less chance to soname changes to break my system, the less code I build, the slighter the chances of having security problems.
Anyway, starting tomorrow I’ll try to continue fixing the modular x dependencies of KDE, hopefully that will mean that it would be possible to install kde without having to merge xorg-x11 at all 😛
And of course where it makes sense, for extensions that people might not want at all, I’ll try to provide useflags 🙂