requirements: introduce a set of working directory specific requirements...
requirements: introduce a set of working directory specific requirements
Some requirements like the SPARSE_REQUIREMENT is working directory specific and
cannot be shared. We add a set which will contain all these requirements.
This is not the best we can do, I think having a rich requirement class will be
much better but that will be out of scope for this series.
Differential Revision:
https://phab.mercurial-scm.org/D8924
