Revert "chore, suffice to compile intrinsics"

This reverts commit eac2bd61f2b0e9b15f1b95ad0c7dfd2bd31278a8.

Well, it doesn't suffice.  gcc happily compiles the code with an
implicit declaration.
chore, emit conditional for popcnt intrinsics
minor, conditionalise on popcnts in co_match()

This is the very place it shouldn't be done in, but seeing as
glep2 is going to be merged with glep at some point, who cares.
Merge branch 'bld/dist'

* bld/dist:
  minor, conditionalise on popcnts in co_match()
  chore, emit conditional for popcnt intrinsics
  Revert "chore, suffice to compile intrinsics"