[syslinux] [PATCH 3/3] Make configure an order-only prerequisite of aconfig.h.in

[Ron]

On Thu, Jul 31, 2014 at 06:58:03AM -0700, H. Peter Anvin wrote:
> On 07/30/2014 11:59 PM, Ron Lee wrote:
> > From: Ron <ron at debian.org>
> > 
> > On filesystems with subsecond resolution, like ext4, we can't trust the
> > timestamp of aconfig.h.in since autoheader leaves it truncated to second
> > resolution (apparently touch -r and cp -p can do this at the very least)
> > while configure has full subsecond resolution, so it can look newer even
> > when it was cleanly created first, leading to the build system looping
> > trying to recreate all of that again ...
> > 
> 
> This sounds like coreutils bugs.

Yeah, I didn't trace this deeper (yet), but I agree something is broken
to be doing that.  For the moment I just wanted to get parallel builds
unbroken, and the order-only dep there is correct in its own right,
aconfig.h.in shouldn't need to be rebuilt if configure changes, we just
want the rule which generates configure to be run before it.

The timestamp issue is known and documented here:
https://www.gnu.org/software/autoconf/manual/autoconf-2.65/html_node/Timestamps-and-Make.html

  Ron