http://dwim.hu/project/hu.dwim.perec

Davit Lichteblau and Tomas Hlavaty have an extensive fork. Merging is
considered, but not planned in the near future (as of 2017).

http://src.knowledgetools.de/tomas/porting/

to be merged:
564c473bfc41e7bc19472eceaa317d283e050e0a
903f1c33989f2955178595f4c3b47f2e782248bc
8ef51dd78778c3c052ef63c2dcbfa4ee8dd25855