Mark things which generate cffi for change detection (#5883)
Mark things which generate cffi for change detection (#5883)

Right now, modifications to native.py don't trigger re-generation of the
native_engine.c file, which leads to a stale engine being used.
wisechengyi/pants,tdyas/pants,benjyw/pants,benjyw/pants,twitter/pants,tdyas/pants,twitter/pants,pantsbuild/pants,pantsbuild/pants,baroquebobcat/pants,jsirois/pants,pantsbuild/pants,baroquebobcat/pants,pantsbuild/pants,tdyas/pants,pantsbuild/pants,twitter/pants,benjyw/pants,baroquebobcat/pants,benjyw/pants,baroquebobcat/pants,wisechengyi/pants,pantsbuild/pants,wisechengyi/pants,wisechengyi/pants,tdyas/pants,twitter/pants,wisechengyi/pants,tdyas/pants,jsirois/pants,wisechengyi/pants,wisechengyi/pants,benjyw/pants,baroquebobcat/pants,baroquebobcat/pants,twitter/pants,twitter/pants,baroquebobcat/pants,tdyas/pants,benjyw/pants,baroquebobcat/pants,twitter/pants,tdyas/pants,pantsbuild/pants,jsirois/pants,tdyas/pants,benjyw/pants,twitter/pants,tdyas/pants,baroquebobcat/pants,wisechengyi/pants,twitter/pants,wisechengyi/pants