Merge branch 'bc/more-git-var'

Add more "git var" for toolsmiths to learn various locations Git is
configured with either via the configuration or hardcoded defaults.

* bc/more-git-var:
  var: add config file locations
  var: add attributes files locations
  attr: expose and rename accessor functions
  var: adjust memory allocation for strings
  var: format variable structure with C99 initializers
  var: add support for listing the shell
  t: add a function to check executable bit
  var: mark unused parameters in git_var callbacks

diff --cc attr.c
Simple merge

diff --cc builtin/var.c
index 214999898079454affe0882be5b4e7a24a7a569b,ef45710a2053419cc49d3f2f42aea3e1c6996afa..3e3d4a6ebf278bdde60859e546bcd7381d9208d6
--- 1/builtin/var.c
--- 2/builtin/var.c
+++ b/builtin/var.c
@@@ -9,6 -10,6 +10,8 @@@
  #include "ident.h"
  #include "pager.h"
  #include "refs.h"
++#include "path.h"
++#include "strbuf.h"
  
  static const char var_usage[] = "git var (-l | <variable>)";
  

diff --cc t/README
Simple merge

diff --cc t/test-lib-functions.sh
Simple merge