4.7.2 install fails on Raspberry Pi

[Bela Markus]

After spending few days no success to install it. If ARM CPU type and 
floating not specified either in C/CXX flags or as config options libgcc 
compile etst with xgcc fails due to unsupported processor instructions. 
It's clear, can be accepted. Specifying proper options xgcc test fail 
due to mismatch of cpu specifications. It is a 4.7.2 specific bug as 
same build script installs 4.6.3 properly.

Bela