Revert #a09246191120: cc/gcc: fix C++ headers location

This was intended as a fix for g++ not finding its headers,
but it breaks in othe horrible ways. So just revert it.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

reporter_name="Harold Grovesteen"

reporter_url="http://sourceware.org/ml/crossgcc/2009-11/msg00052.html"

reporter_comment=""