Re: On overriding make variables from the environment...

From: Jonathan Nieder <jrnieder@gmail.com>
To: "SZEDER Gábor" <szeder.dev@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: On overriding make variables from the environment...
Date: Tue, 16 Oct 2018 14:54:56 -0700	[thread overview]
Message-ID: <20181016215456.GB96853@aiede.svl.corp.google.com> (raw)
In-Reply-To: <20181016184537.GN19800@szeder.dev>

Hi,

SZEDER Gábor wrote:

> Our Makefile has lines like these:
>
>   CFLAGS = -g -O2 -Wall
>   CC = cc
>   AR = ar
>   SPATCH = spatch
>
> Note the use of '=', not '?='.
[...]
> I'm not sure what to do.  I'm fine with updating our 'ci/' scripts to
> explicitly respect CC in the environment (either by running 'make
> CC=$CC' or by writing $CC into 'config.mak').  Or I could update our
> Makefile to use '?=' for specific variables, but:

That's a good question.  I don't have a strong opinion myself, so I
tend to trust larger projects like Linux to have thought this through
more, and they use 'CC = cc' as well.  So I'd lean toward the updating
'ci/' scripts approach, to do something like

	make ${CC:+"CC=$CC"} ...

(or the equivalent multi-line construction).

That also has the bonus of being explicit.

Just my two cents,
Jonathan