[PATCH] build: fix out-of-tree builds

[David Bremner]

Jani Nikula <jani at nikula.org> writes:

> On Wed, 15 May 2013, David Bremner <david at tethera.net> wrote:
>> Jani Nikula <jani at nikula.org> writes:
>>>  # List all subdirectories here. Each contains its own Makefile.local
>>> -subdirs := compat completion emacs lib man parse-time-string
>>> -subdirs += performance-test util test
>>> +subdirs = compat completion emacs lib man parse-time-string performance-test util test
>>
>> Is this a functional change or a cosmetic one?
>
> Functional. All of it seems to be required for out-of-tree builds (*) to
> work. I'm afraid I've forgotten exactly why both := and += make it fail
> (I wrote the patch a few months ago).
>

Still I guess it deserves a comment so we don't break it again?

d