chore, guard fastterms(1) tests by HAVE_INTRIN too

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
chore, explicitly check for _tzcnt_u32() and __tzcnt_u32()

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'tool/fastterms'

* tool/fastterms:
  chore, explicitly check for _tzcnt_u32() and __tzcnt_u32()
  chore, guard fastterms(1) tests by HAVE_INTRIN too