[build] Avoid using sha1sum when calculating build ID

The sha1sum command may not be available on all systems.  Use the
POSIX-confirming cksum instead.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
1 file changed
tree: e67f0ffcb875815a882764f618881e78e9c8d356
  1. contrib/
  2. src/
  3. .travis.yml
  4. COPYING
  5. COPYING.GPLv2
  6. COPYING.UBDL
  7. README