add cloog-0.18.0.tar.gz

Needed by GCC 4.8+ to enable graphite framework for loop optimizations

Change-Id: I2f6f1f1d608f44ab15c0d441773fff8e3d7ef494
Unpack cloog-*.tar.gz and remove the archives

.. autom4te.cache folders and .gitignore files
that shouldn't have been in the archives were
also removed. The .gitignore files related to
the original git repositories and caused fixes
to e.g. configure to be ignored.
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.
Add .gitignore