Support git subtree

[debuglevel]

git subtree does not work on current the default image:

$ git subtree
git: 'subtree' is not a git command. See 'git --help'.

It is actually available at /usr/lib/git-core/git-subtree and works if you call it by its full path.

$ find / -name '*subtree*' 2> /dev/null
/usr/lib/git-core/git-merge-subtree
/usr/lib/git-core/git-subtree
/usr/share/man/man1/git-subtree.1.gz
/usr/share/doc/git/contrib/subtree
/usr/share/doc/git/contrib/subtree/t/t7900-subtree.sh
/usr/share/doc/git/contrib/subtree/git-subtree.sh
/usr/share/doc/git/contrib/subtree/git-subtree
/usr/share/doc/git/contrib/subtree/git-subtree.txt
/usr/local/libexec/git-core/git-merge-subtree

[sardorb3k]

https://cogumbreiro.blogspot.com/2013/05/how-to-install-git-subtree-in-ubuntu.html

[debuglevel]

The command sudo ln -s /usr/share/doc/git/contrib/subtree/git-subtree.sh /usr/lib/git-core/git-subtree suggests that it's only necessary to link /usr/share/doc/git/contrib/subtree/git-subtree.sh to /usr/lib/git-core/git-subtree. As shown above, this is already available.

[kallayj]

Running git --exec-path returns /usr/local/libexec/git-core. git-subtree is missing from that directory. /usr/local/libexec contains only the git-core directory, so special care was taken to run git out of this directory (presumably to ensure git commands are auto-magically integrated with Github). I'm curious if subtree is intentionally or accidentally excluded.