configure: Simplify an expression with enabled_all.
Merge commit '6dc6598692da3b0ebda2d768681786343f26a4f4'

* commit '6dc6598692da3b0ebda2d768681786343f26a4f4':
  configure: Simplify an expression with enabled_all.

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