Log Message:
sqlite3: do not accept builtin versions any longer

Since pkgsrc can't tell what features are enabled, and at least
NetBSD's sqlite3 was not meant to be used by pkgsrc (it was built
with minimal features enabled, for heimdal support).

Also do not accept heimdal from NetBSD versions where it linked against
sqlite3 (fixed in NetBSD-current) to avoid pulling in two different
versions of sqlite3 into binaries when depending both on heimdal and
sqlite3.

Inspired by PR 58448, and discussed on tech-pkg.