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

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Oct 16, 2018, 21:54 UTC
Message-ID: <20181016215456.GB96853@aiede.svl.corp.google.com>
In-Reply-To: <20181016184537.GN19800@szeder.dev>

Hi,

SZEDER Gábor wrote:

Show 8 quoted lines

> 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