scripts: fix tools override

The tools found by the new autostuff configure can contain arguments,
for example: grep -E

This needs separating the paths set for the Makfile from the paths
set for the scripts.

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

reporter_name="Kevin Cernekee"

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

reporter_comment="MIPS SDE-compatible toolchain"