configure: check for -march and -mtune passed via CC
authorAndre McCurdy <armccurdy@gmail.com>
Tue, 21 Apr 2015 17:34:05 +0000 (10:34 -0700)
committerRich Felker <dalias@aerifal.cx>
Tue, 21 Apr 2015 17:38:48 +0000 (13:38 -0400)
commita6274a1971b7aa1d12fdce3d040f847539a71049
treeadc522bcde7a7d91fc665fb2fb32cc8d0731ddd4
parentea1b6bb6123d2177508ddca438669ec96cfa0021
configure: check for -march and -mtune passed via CC

Some build environments pass -march and -mtune as part of CC, therefore
update configure to check both CC and CFLAGS before making the decision
to fall back to generic -march and -mtune options for x86.

Signed-off-by: Andre McCurdy <armccurdy@gmail.com>
configure