postgresql74-client shouldn't require readline

[Chris Ross <cross+netbsd%distal.com@localhost>]

  The documentation for building Postgres 7.4.x clearly indicates that 
while
readline is desireable, that on NetBSD, libedit (a normal installed 
system
library) is acceptable and will be used if readline can't be found.

  But the pkg for postgres74-client lists readline as a requirement, so
the system builds and installs it, without letting the postgres build 
process
simply use the existing libedit library.

  This seems broken to me.  Does someone know of a good reason why
libedit isn't sufficient?  If not, can we please fix it to not require 
the libreadline
package?

  Thanks...

                             - Chris