=> Bootstrap dependency digest>=20010302: found digest-20121220
=> Checksum SHA1 OK for twm-1.0.7.tar.bz2
=> Checksum RMD160 OK for twm-1.0.7.tar.bz2
===> Installing dependencies for twm-1.0.7
=> Tool dependency pkg-config>=0.25: found pkg-config-0.28
=> Build dependency x11-links>=0.72: found x11-links-0.74
=> Build dependency xbitmaps>=1.0: found xbitmaps-1.1.1
===> Overriding tools for twm-1.0.7
===> Extracting for twm-1.0.7
===> Patching for twm-1.0.7
===> Creating toolchain wrappers for twm-1.0.7
ERROR: zlib>=1.1.4nb1 is not installed; can't buildlink files.
*** Error code 1

Stop.
bmake: stopped in /usr/pkgsrc/wm/twm
*** Error code 1

Stop.
bmake: stopped in /usr/pkgsrc/wm/twm