From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jonathan Nieder <jrnieder@gmail.com>
Subject: Re: [PATCH resend] Makefile: Use computed header dependencies if the
 compiler supports it
Date: Thu, 18 Aug 2011 13:41:42 -0500
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Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>
To: Fredrik Kuivinen <frekui@gmail.com>
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Fredrik Kuivinen wrote:

> Oh, I missed "--help". But for me gcc always exits with status code 0
> when I give it "--help", regardless of what other flags I
> provide. Therefore, I don't see how "--help" can be used to test for
> support of -MMD.

Ah, my mistake.  Good catch.

> Here is an updated patch. It avoids the ++empty.c file by giving "-x
> c" to the compiler.

Much nicer, thanks!

> It also avoids the auto-detection when
> COMPUTE_HEADER_DEPENDENCIES is set

Unfortunately "ifdef" in Makefiles means "if nonempty", so the
overhead of detection is still there if I want to explicitly disable
COMPUTE_HEADER_DEPENDENCIES.  That's okay, since that overhead is
small.  So for what it's worth,

Acked-by: Jonathan Nieder <jrnieder@gmail.com>