Merge branch 'jc/custom-comment-char'

Allow a configuration variable core.commentchar to customize the
character used to comment out the hint lines in the edited text from
the default '#'.

* jc/custom-comment-char:
  Allow custom "comment char"

cache.h

@@ -563,6 +563,12 @@ extern int core_preload_index;
 extern int core_apply_sparse_checkout;
 extern int precomposed_unicode;
 
+/*
+ * The character that begins a commented line in user-editable file
+ * that is subject to stripspace.
+ */
+extern char comment_line_char;
+
 enum branch_track {
 	BRANCH_TRACK_UNSPECIFIED = -1,
 	BRANCH_TRACK_NEVER = 0,