buildroot

toolchain: add gcc 4.6.0

Add gcc 4.6.0 to the toolchain repertoire:

Target gcc is known to be broken in some scenarios.

This version is considered experimental so things may break.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>