Add configure path to libgpgerror in case homebrew is installed in
a non-standard location where gpg error libraries and includes are
not automagically found.
Signed-off-by: Adam Vandenberg <flangy@gmail.com>
brewkit.rb changes ENV destructively, so lets not do that everytime a formula
is required. Now it's possible for other tools to require a formula
description without worrying about side-effects.
