functions: also honor .abuild file at gitbase

This permits introducing branch-specific modifications to abuild.conf settings.
Any settings there override /etc/abuild.conf and $HOME/.abuild/abuild.conf.

functions.sh.in

@@ -46,6 +46,8 @@ readconfig() {
 			APORTSDIR=
 		fi
 	fi
+	# source any .abuild file at the aports root, but only if we are currently in aports tree
+	[ -n "$APORTSDIR" ] && [ -f "$APORTSDIR/.abuild" ] && [ "$APORTSDIR" = "$gitbase" ] && . "$APORTSDIR/.abuild"
 	BUILDDIR=${_BUILDDIR-$BUILDDIR}
 	PKGDEST=${_PKGDEST-$PKGDEST}
 	SRCPKGDEST=${_SRCPKGDEST-$SRCPKGDEST}