Okay, so I will show you the details of how I did it:
It was not possible. It is a pain to need Qt installed, but I did not find a way around it. X is not needed, Qt is. I succeeded installing, but not without GUI components.
I am using Gentoo. Most pain is compiling Qt-Webkit, because of low memory (linking takes about 700MB RAM, 128MB are available, and distcc does
not help in this case; and I don't think calibre is ever using it). If you want to work around this problem, try what is described in the Gentoo Embedded handbook (Compiling with qemu-user chroot):
http://www.gentoo.org/proj/en/base/e...?part=1&chap=5 , speeds it up from a few days (I stopped it after 4 days) to about 2 hours. You simply run your system off an USB stick at your PC emulating ARM. Hope it helps other people running Gentoo and trying to install calibre and waiting for years to get Qt working...