Arch wiki Font Configuration page recommends the following:
Ubuntu uses the original LCD patched packages and adds extra configurations, and occasionally patches.
First, the conflicting packages need to be removed:
pacman -Rd libxft cairo fontconfig freetype2
Then install the patched packages from the AUR using an AUR helper of your choice. The package names are:
freetype2-ubuntu fontconfig-ubuntu libxft-ubuntu cairo-ubuntu
Halfway the installation I get into problems because there are some dependency problems and not all the ubuntu packagescan be installed. The lxterminal comes to a halt and when rebooting I can't login.Well I login but get thrown back.
The only solution in this case i sto start another terminal session at the login by doing Ctrl+Alt+F2.
In terminal session on tty2 I first uninstall what was recently installed.If you don't know exactly any more what was installed and not, just try everything, what you told pacman to do: sudo pacman -Rd packagename1 then on with package2 etc.In this situation I did it one for one to get precise feedback.Then I reinstalled freetype2 cairo libxft and fontconfig in this order.This all seems rather easy but it took me some experimenting to find out what went wrong. Didn't realize that a wrecked fontconfig could have such devastating effects.
But as always the most recent changes will be responsible for what wrecked your system.