Can git ignore parts of files

[Alan <alan@clueserver.org>]

I have kind of an odd problem that is causing me grief in git.  I figure
someone has a good solution here.  (Or not, they will soon.)

I have a couple of kernel .config files that are checked into git.  They
are used to test kernel configurations for the nightly builds where I
work.

We have a bunch of kernel developers working on drivers.  When they add
a new driver, they add in the options in the test file to make it
compile in the test builds.

The problem is that the kernel config file has a timestamp at the top of
the file that is generated by "make oldconfig" or "make config".  Other
than removing the timestamp each time manually, is there a way to get
git to ignore the timestamp on a merge?

What happens is that the authors submit the changes on a branch in most
cases.  Sometimes they have a version of that file that is quite out of
date.  When I go to merge, that one file gives me grief 95% of the time.

Is there an easy way around this?  Am I approaching the problem wrong?
Is there a better way to do this?