Merge branch 'rj/clean-speedup'

Speed up 'make clean' on Cygwin. * rj/clean-speedup: Makefile: conditionally include GIT-VERSION-FILE

Pratyush Yadav committed Dec 18, 2020 at 00:42 UTC 796f6525b1338d9c325aba8c311994cb12e69b2c

No changes.