unzip 6.0

OS X <=10.8 have unzip < 6, which don't support ZIP64 files
apr 1.4.6

Closes #90.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
apr-util 1.5.1

Closes #91.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
units 2.01

Closes #114.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
openldap: specify sysconfdir so config persists
openldap: use optional dep
Bison moved to homebrew as keg-only.