file's sole purpose was to provide a dependency on pkg-config and set
some environment variables. Instead, turn pkg-config into a "tool"
in the tools framework, where the pkg-config wrapper automatically
adds PKG_CONFIG_LIBDIR to the environment before invoking the real
pkg-config.
For all package Makefiles that included pkg-config/buildlink3.mk, remove
that inclusion and replace it with USE_TOOLS+=pkg-config.
This is a significant rework of the "gramps" genealogical database
(databases/gramps in pkgsrc), in particular it uses a bsd/sleepycat
binary database now an d alot of the GNOME framework.
Thanks to Jeremy C. Reed for ideas and patches.
