[PATCH 1/3] gitweb: Add option to force version match

This adds $git_versions_must_match variable, which is set to true,
checks that we are running on the same version of git that we
shipped with, and if not throw '500 Internal Server Error' error.
What is checked is the version of gitweb (embedded in building
gitweb.cgi), against version of runtime git binary used.

Gitweb can usually run with a mismatched git install.  This is more
here to give an obvious warning as to whats going on vs. silently
failing.

By default this feature is turned on.

Signed-off-by: John 'Warthog9' Hawley <warthog9@kernel.org>
Signed-off-by: Jakub Narebski <redacted>
---
 gitweb/README      |    4 ++++
 gitweb/gitweb.perl |   27 +++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 0 deletions(-)