explicitly mark isl_basic_set_drop_constraint as deprecated
explicitly mark isl_basic_set_drop_constraint as deprecated

It was deprecated in f54384e (deprecate isl_basic_set_drop_constraint,
Fri Feb 20 11:09:27 2015 +0100).

Signed-off-by: Sven Verdoolaege <e5350bbed4977f5eb8ae1dc6abd9ae59d21ace75@kotnet.org>

tobig/isl,UBERTC/isl,nicolasvasilache/isl,PollyLabs/isl,tobig/isl,inducer/isl-mirror,tobig/isl,PollyLabs/isl,Meinersbur/isl,inducer/isl-mirror,UBERTC/isl,UBERTC/isl,inducer/isl-mirror,UBERTC/isl,PollyLabs/isl,Meinersbur/isl,nicolasvasilache/isl,nicolasvasilache/isl,Meinersbur/isl,inducer/isl-mirror,tobig/isl,PollyLabs/isl,inducer/isl-mirror,nicolasvasilache/isl,Meinersbur/isl,PollyLabs/isl,nicolasvasilache/isl