This reverts commit 2624f9079617df6b1fffda8c10f6a7a35068ecdc, reversing
changes made to 37aab4cbb5552bf021b20cf05d64e8ded6f3538a.
See:
https://github.com/NixOS/nixpkgs/pull/42376#issuecomment-399789096
Basically this breaks at least some users of fetchgit,
so let's revert this until this is sorted out.
Git's Makefile has a NO_INSTALL_HARDLINKS flag to produce symlinks
instead of hard links. However, it still produces hard links between
$out/bin and $out/libexec, hence the patch.
Also, update Git to 1.8.2.1.