[PATCH 0/3] Additional variables for git var

On many Unix systems, we have a good idea where Git's configuration files and the shell it uses are located. However, there are some systems where that's not the case, such as Windows and with Homebrew, where the expected files might be found in another location.

Right now, programs who would like to access things like the system gitattributes or config file have to guess where the distributor of Git placed these files, and with runtime relocation, it's not even guaranteed that these will be in a fixed place from invocation to invocation. As a result, we need a way to query Git about the location of these files.

This series introduces five new configuration variables that refer to the shell path, the system and global gitattributes files, and the system and global config files. The global values are not technically needed, since they should be computable from the environment alone, but they are added to make life easier for users.

The shell path is especially useful on Windows, where Git usually provides the POSIX shell, and is designed to make using programs that interact with Git or Unix-like environment variables (e.g., `EDITOR` and `VISUAL`) easier.

The gitattributes files are primarily for the benefit of Git LFS, but of course the goal is to be generally useful.

The curious reviewer may ask, "Why are these in `git var` and not `git rev-parse`?" The answer is that these refer to configuration (albeit partially at compile time), and thus are like the existing GIT_EDITOR, and unlike what `git rev-parse` produces, which is almost completely limited to paths and metadata related specifically to a given repository.

This should be a relatively straightforward series, but of course any feedback is welcome.

brian m. carlson (3):
  var: add support for listing the shell
  var: add attributes files locations
  var: add config file locations

 Documentation/git-var.txt | 23 +++++++++
 attr.c                    |  6 +--
 attr.h                    |  4 ++
 builtin/var.c             | 99 +++++++++++++++++++++++++++++++++++----
 t/t0007-git-var.sh        | 98 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 219 insertions(+), 11 deletions(-)