Bug#887664: openal-soft: FTBFS: nothing is built

[Simon McVittie]

On Fri, 19 Jan 2018 at 09:03:15 +0000, Simon McVittie wrote:
> Declaring the build target as "phony" is meant to solve this,
> and has worked since at least 2009, so I'd prefer to understand why
> that's apparently stopped working recently.

I think this might only have worked by mistake: fixing
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=880840
looks like a plausible reason for it to have regressed.

In https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=880840#20,
James Cowgill wrote:
> Make ignores implicit rules (like %: dh $@) for phony targets.

So we were meant to either do:

.PHONY: build
build:
	(insert a duplicate of the implicit rule for % here)

or delete the directory; but it happened to work anyway because of a
debhelper bug (#880840) which has now been fixed.

    smcv