MinGW-w64 build fix (lacks ffs declaration)

Define ffs as __builtin_ffs if ffs is not declared but
__builtin_ffs is declared.

This problem only happens at -O0 as one of the optimization
passes substitutes ffs for __builtin_ffs.

.. this patch has been submitted to the ISL project and also
apparently merged, though it is not in the publically visible
repository yet.
15 files changed
tree: d5689a8fa45ad1c06b9e2fe97bdcdae3eb4f0184
  1. cloog-0.16.3/
  2. cloog-0.17.0/
  3. cloog-0.18.0/