configure: Enable the strtod workaround when building for bionic

Signed-off-by: Martin Storsjö <martin@martin.st>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  configure: Enable the strtod workaround when building for bionic

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avienc: Disallow the first frame to be skiped

Fixes Ticket2386

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>