This is basically a plain copy-paste announcement from yngwin's blogie :)

---------

This is basically a heads-up for Qt users on Gentoo. We are about to add the 
new 4.5.2 release to portage. With this release we have changed a few things. 
We no longer have certain useflags enabled by default that are already enabled 
by the desktop profile. This means that if you are not using the desktop 
profile, you should look if any useflags have changed and decide which ones you 
want to enable. Or otherwise, that you no longer need to disable them if you 
want a minimal install.
We also have removed the need for the libX11 dependency in qt-core and a 
couple of other non-gui modules. So you can now for example have a server-only 
install of quassel with minimal dependencies. The libX11 dependency is now 
only pulled by packages that really need it.
Another thing that changed is that we dropped the custom-cxxflags useflag. After 
a long period of testing we haven’t come across any problems with “advanced” 
cxxflags in Qt 4.5, so now we always let the Qt modules be built with the user-
specified flags. As this is an eclass level change, this means also users of the 
stable branch will see this change. An emerge --newuse world will trigger a 
recompile of Qt, but this means you will get better optimizations.
------------

Link: http://ben.liveforge.org/2009/06/27/qt-452-changes

Enjoy your Qt experience :)
-- 
Markos Chandras (hwoarang)
Gentoo Linux Developer [KDE/Qt/Sunrise/Sound]
Web: http://hwoarang.silverarrow.org