bug#25971: POSIX path separator used in cfg.mk breaks makefiles for all OS that do not use colon as path separator

[Jim Meyering]

pushed:

  
http://git.savannah.gnu.org/cgit/grep.git/commit/?id=70032889a81f2dd391e5053dadb9b697e94107b6
  
http://git.savannah.gnu.org/cgit/grep.git/commit/?id=dff64f9ededbea38f573e06967e85f15a1c46e4a