[PATCH] git.el: handle default excludesfile properly

[Dorab Patel <dorabpatel@gmail.com>]

The previous version only looked at core.excludesfile for locating the
excludesfile.  So, when core.excludesfile was not defined, it did not
use the possible default locations.

The current version uses either $XDG_CONFIG_HOME/git/ignore or
$HOME/.config/git/ignore for the default excludesfile location
depending on whether XDG_CONFIG_HOME is defined or not.  As per the
documentation of gitignore.

Signed-off-by: Dorab Patel <dorabpatel@gmail.com>
---
 contrib/emacs/git.el | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/contrib/emacs/git.el b/contrib/emacs/git.el
index 97919f2d7..16c6b4c05 100644
--- a/contrib/emacs/git.el
+++ b/contrib/emacs/git.el
@@ -757,8 +757,12 @@ Return the list of files that haven't been handled."
 
 (defun git-get-exclude-files ()
   "Get the list of exclude files to pass to git-ls-files."
-  (let (files
-        (config (git-config "core.excludesfile")))
+  (let* (files
+	 (defaultconfig (if (getenv "XDG_CONFIG_HOME")
+			    (concat (file-name-as-directory (getenv "XDG_CONFIG_HOME")) "git/ignore")
+			  (concat (file-name-as-directory (getenv "HOME")) ".config/git/ignore")))
+	 (coreexcludes (git-config "core.excludesfile"))
+	 (config (if coreexcludes coreexcludes defaultconfig)))
     (when (file-readable-p ".git/info/exclude")
       (push ".git/info/exclude" files))
     (when (and config (file-readable-p config))
-- 
2.16.2