From: Jonathan Nieder Date: Thu, 18 Aug 2011 18:41:42 GMT Subject: Re: [PATCH resend] Makefile: Use computed header dependencies if the compiler supports it Message-ID: <20110818184142.GF30436@elie.gateway.2wire.net> In-Reply-To: <20110818183439.GA21560@fredrik-Q430-Q530> 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