Move generation of build.h into a shell script

Moving the routines that create build.h into a script offers
several advantages.  We can create more complex functions to
run and we don't have to deal with both bash and Make at the same
time.

This script combines what is currently in Makefile.inc with a
couple of updates.
- Update how it determines whether to use git for the timestamp
- Move the git revision string generation inside the routine
that checks to see if we have git.
- Add a timeout for the domain name check.

Change-Id: I93c131e8d01a0099eb13db720fa865c627985750
Signed-off-by: Martin Roth <gaumless@gmail.com>
Reviewed-on: http://review.coreboot.org/8428
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2 files changed