configure: look for more usual g-variants of some tools

Reported-by: Bryan Hundven <bryanhundven@gmail.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 reporter_name="Kevin Cernekee"

 reporter_url="http://sourceware.org/ml/crossgcc/2011-09/msg00037.html"

 reporter_comment="MIPS SDE-compatible toolchain"