Fixed cabal file so it compiles on OpenBSD
Fixed cabal file so it compiles on OpenBSD

OpenBSD still packages a version of OpenLDAP prior to 2.4 therefore one
macro differs in the ldap.h headers. Tested on a fairly recent Archlinux
x86_64 and on OpenBSD 4.7 and 4.8 i386.

wferi/ldap-haskell,ezyang/ldap-haskell