If a port used other USE_GNOME items it was untouched.
The ports that used other USES were fixed by hand.

PR:		ports/177081
Reviewed by:	bapt
Approved by:	portmgr (miwi)

are no more self hosting so we are stuck with 0.25 version while pkgconf provide
the same set of features as 0.27 and a compatible frontend. A symlink to
pkg-config has been added for convenience and compatibility

This also introduces a new macro to use pkgconf in your ports:
USE_PKGCONFIG

it can take the following arguments:
 - yes (meaning build only dep)
 - build (meaning build only dep)
 - run (meaning run only dep)
 - both (meaning run and build dep)

From now USE_GNOME= pkgconfig is deprecated in favour of USE_PKGCONFIG
The old gnome macro has been modified to use pkgconf but still the sameway: run
and build dep to avoid large breakage.

While here fix some ports relying on pkg-config but not specifying it, fix some
ports broken because testing wrong .pc files, and fix ports using pkg-config
--version to determine pkg-config version instead of
pkg-config --modversion pkg-config like recommanded by pkg-config

With Hat:	portmgr
Exp-runs by:	bapt (pointhat-west), beat (pointyhat)

convert it to BUILD_DEPENDS. This avoids the problem of the bogus run dep
added by bsd.gnome.mk.

- Fix all ports that add {CPP,LD}FLAGS to *_ENV to modify flags instead

PR:		157936
Submitted by:	myself
Exp-runs by:	pav
Approved by:	pav