I was able to install Altera Quartus7.2 for Linux into Gentoo Linux. Before installing, do the following (as root):
1. Install tcsh by

2. Create emulation command for "arch" by creating file /bin/arch, containing the following:
==== Begin Cut Here ===

uname -m
==== End Cut Here ====
chmod a=rx /bin/arch

Before using the commands such as "nios2-config-sof", "nios2-download", do the following as a work around to change USB port permission (as root):
chmod -R 777 /proc/bus/usb

Then start using the Altera tools with a regular user login.