=> Bootstrap dependency digest>=20010302: found digest-20121220
=> Checksum SHA1 OK for xsel-1.2.0.tar.gz
=> Checksum RMD160 OK for xsel-1.2.0.tar.gz
===> Installing dependencies for xsel-1.2.0
=> Build dependency x11-links>=0.72: found x11-links-0.74
===> Overriding tools for xsel-1.2.0
===> Extracting for xsel-1.2.0
===> Patching for xsel-1.2.0
=> Applying pkgsrc patches for xsel-1.2.0
===> Creating toolchain wrappers for xsel-1.2.0
ERROR: zlib>=1.1.4nb1 is not installed; can't buildlink files.
*** Error code 1

Stop.
bmake: stopped in /usr/pkgsrc/x11/xsel
*** Error code 1

Stop.
bmake: stopped in /usr/pkgsrc/x11/xsel