[SeaBIOS] [PATCH] build: remove hardcoded timestamp

[Kevin O'Connor]

On Tue, Feb 03, 2015 at 04:38:15PM +0000, Ian Campbell wrote:
> On Tue, 2015-02-03 at 10:58 -0500, Kevin O'Connor wrote:
> > On Tue, Feb 03, 2015 at 01:23:53PM +0100, Olaf Hering wrote:
> > > The timestamp and hostname carries no value for the default build. If
> > > its really required in special environment, or if someone is emotionally
> > > attached to such strings, it is is handled by existing logic a few lines
> > > above: provide your own .version file
> > > 
> > > Once this patch is applied it is possible to get reproducible builds of
> > > Xens hvmloader.
> > 
> > I've found the version information to be quite helpful when we get
> > trouble reports - it helps indicate what was being run and who built
> > the code (eg, distribution or local).  During development cycles, it
> > helps verify that test runs are executed with the expected code.
> > 
> > What breaks if the version changes?
> > 
> > It should be possible to force a static version with "make
> > VERSION='xyz'", but I'd ask that that not be done for production
> > builds as it makes handling trouble reports harder.
> 
> Olaf posted some similar patches against Xen and it was suggested that
> using the git HEAD time and/or "git describe" would help.
> 
> We could probably arrange to do this when building SeaBIOS as part of
> Xen, or for tarball rather than git builds use the Xen release version?

SeaBIOS uses "git describe" as part of its version string today, and
for SeaBIOS tar releases we embed a ".version" file with the release
info (see scripts/buildversion.sh and scripts/tarball.sh for details).

Even with this, the build timestamp is still useful during development
cycles (when the head may be dirty).  And the hostname/timestamp are
useful as a way of backtracking to the gcc/binutils environment on
trouble reports even from official releases.

-Kevin