nss' own zlib, dbm

[Mikhail T.]

Hi!

Thank you for accepting most of my changes for nss (and all of them for
nspr).

May I ask, why did you leave NSS to build its own zlib and dbm, however?

Every OS has zlib these days and NSS is planning to drop it from their
distribution:

	https://bugzilla.mozilla.org/show_bug.cgi?id=302670

Also, FreeBSD happens to have an equivalent of their dbm in -lc. This
is, probably, also true for Open and NetBSD and our other siblings.

	-mi