toolchain: make target gcc a working option

Make target gcc a more usable option.

* Nuke duplicate libgcc_s*.so* in /usr/lib since it confuses target gcc
* Copy *crt*.o files to the target system to unbreak gcc

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