ports-mgmt/portlint: fix missing variable expansion in *_DEPENDS

[jrm]

Summary

BUILD_DEPENDS= ${PKGNAMEPREFIX}${PORTNAME}>=0:x11/${PKGNAMEPREFIX}${PORTNAME}

% portlint
WARN: Makefile: no port directory /usr/ports/x11/${PKGNAMEPREFIX}clx found, even though it is listed in BUILD_DEPENDS.

This patch ensures that all variables in a *_DEPENDS value are expanded.

[mat]

(Note that portlint is a third party tool, it is not developped in the ports tree, nor is it the responsability of portmgr, best create a PR with your patches.)

[jrm]

Ok. https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=221605

[jrm]

Committed to 2.17.13.