Handling of mscore/revision.h
-----------------------------

The copy of mscore/revision.h in the git repository is just a default, to
prevent build failures from a freshly cloned or checked-out repo. It contains
the string "Unknown" instead of a build number.

It is always possible to update mscore/revision.h with the build number
of the current checked-out branch by doing "make revision". However, the
updated mscore/revision.h should never be committed back to git. This can
be prevented manually by restoring the original value before committing,
with "git checkout -- mscore/revision.h"

But there is an easier way to achieve all this automatically...

The post-checkout script in this directory should be installed as a hook in
git, and will update mscore/revision.h with the branch number automatically
when checking out a new branch.

The hook also does "git update-index --assume-unchanged mscore/revision.h",
so that git does not expect the updated mscore/revision.h file to be staged
or committed. It also stops it from showing up in "git diff" or "git status".

To install the hook from this directory, do:

$ cp -p post-checkout ../../../.git/hooks/

Alternatively from the top-level directory, do:

$ cp -p build/git/hooks/post-checkout .git/hooks/

This only needs doing once, and works for Linux, Windows (MinGW) and OSX.
