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="Thomas Petazzoni"

reporter_url="http://www.free-electrons.com/"

reporter_comment="Very basic testing only"