To conserve space/improve file caching we try to make hard or symbolic links
from each builtin program to the main git executable rather than having
each be a complete duplicate copy of it.  We weren't doing this for the
builtin programs residing in the bin directory though.  So, let's do so.
Signed-off-by: NBrandon Casey <casey@nrlssc.navy.mil>
Reviewed-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>