Install git binaries without package management and fix missing helpers

Talk about flexibility. Suppose you need git, but don't have package management or a compiler. What's a SWE to do? Use git's --exec-path feature, which changes the search path for it's helpers, allowing you to install it pretty much anywhere.

$ mkdir ~/opt && cd ~/opt

$ wget http://archive.ubuntu.com/ubuntu/pool/main/g/git-core/git-core_1.7.0.4-1ubuntu0.2_amd64.deb

$ dpkg -x git-core_1.7.0.4-1ubuntu0.2_amd64.deb .

$ export GIT_EXEC_PATH=/home/ppetraki/opt/usr/lib/git-core

$ cd ~/Sandbox

$ ~/opt/usr/bin/git clone git://kernel.ubuntu.com/ubuntu/ubuntu-quantal.git
warning: templates not found /usr/share/git-core/templates
Initialized empty Git repository in /home/ppetraki/Sandbox/ubuntu-quantal/.git/
remote: Counting objects: 2721745, done.
remote: Compressing objects: 100% (419165/419165), done.
Receiving objects:   2% (78914/2721745), 21.36 MiB | 89 KiB/s 

Sweet! This feature also address the git-XXXX helper not found.