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="YEM"

reporter_url="http://ymorin.is-a-geek.org/"

reporter_comment="Sample i586 configuration tweaked to generate code for the geode."