PKG_CONFIG_PATH gets clobbered ?

[John Affleck <lists+garnome lists oddment net>]

So I'm trying garnome-2.12.0 on a system I've had luck building
garnome on in the past.  It's an interesting experience, since it's a
RH 7.1 based box that I don't have root access to.  This means I end
up building a lot of support packages that aren't in bootstrap (Mesa,
libpng, for example) and sticking them somewhere.  This requires that
pkg-config can see this area, and I naively thought that just setting
PKG_CONFIG_PATH would be sufficient.  Turns out that gar.conf.mk
clobbers PKG_CONFIG_PATH, which means that I'm not building against
what I thought I was..

Is there a reason to reset PKG_CONFIG_PATH, or was it just an
oversight ?

	John A.