Re: [RCF/PATCH] Makefile: move 'ifdef DEVELOPER' after config.mak* inclusion

From: Jeff King <peff@peff.net>
Date: Jun 1, 2016, 08:03 UTC
Message-ID: <20160601080348.GA22528@sigill.intra.peff.net>
In-Reply-To: <vpqpos11gv3.fsf@anie.imag.fr>

On Wed, Jun 01, 2016 at 09:57:20AM +0200, Matthieu Moy wrote:

Show 11 quoted lines

> Jeff King <peff@peff.net> writes:
> 
> > Hmm. So I think this does fix some issues, but it also means that one's
> > config.mak cannot use DEVELOPER as a base and then override particular
> > flags.
> 
> You mean, using "make DEVELOPER=1" and then tweak CFLAGS in config.mak?
> 
> Well, you still can do "CFLAGS += ..." (the extra CFLAGS will come
> before the ones added by DEVELOPER instead of after), which should cover
> 99% use-cases.

I specifically meant this, that your flags will now come before the DEVELOPER ones. So they will not override for any options which are parsed in command-line order (e.g., -Wno-error=something-specific).

> You can't do "CFLAGS = $(filter-out ..., $(CFLAGS))" anymore indeed. But
> if you are at that level of customization, I'd say DEVELOPER isn't for
> you and you should just set CFLAGS directly.

Yes, though it would be nice if the developer cflags were in a separate variable to make that easier to play with.

Perhaps:

  DEVELOPER_CFLAGS += -Wfoo
  DEVELOPER_CFLAGS += -Wbar
  ...
  -include config.mak
  ...
  ifdef DEVELOPER
  CFLAGS += $(DEVELOPER_CFLAGS)
  endif

would be more flexible.

I don't currently use filter-out, but I do have compiler-specific flags (which I accomplish by just not adding them in the first place for certain compilers). For example, you may notice that:

  make DEVELOPER=1 CC=clang

is broken (clang doesn't know -Wold-style-declaration).

-Peff