`debian/rules clean` leaves stale debian/linux-libc-dev

[dann frazier]

When building with a non-primary variant - such as the unstable tree[*], do_libc_dev gets set to false:

---- debian/rules.d/0-common-vars.mk ----
# linux-libc-dev may not be needed, default to building it only for the
# primary variant
ifneq ($(filter --,$(variants)),)
do_libc_dev_package=true
else
do_libc_dev_package=false
endif
-----------------------------------------

As well it should. This prevents linux-libc-dev from getting included in debian/control, also good. The problem is that install-arch-headers creates and populates debian/linux-libc-dev/ even if do_libc_dev_dev_package=false. And because linux-libc-dev is not in debian/control, dh_clean doesn't know it should clean it up.

I wonder if the "ifeq ($(do_libc_dev_package),true)" guard in the install-arch-headers needs to cover more of that target.

[*]
ubuntu@starbuck:~/linux$ cat debian.master/variants
-wip