Fix: Compatibility with Org 9.2

Thanks to Brian Leung (@leungbk).  See #49.

Released as 0.3.1.

org-ql.el

@@ -2,7 +2,7 @@
 
 ;; Author: Adam Porter <adam@alphapapa.net>
 ;; Url: https://github.com/alphapapa/org-ql
-;; Version: 0.3
+;; Version: 0.3.1
 ;; Package-Requires: ((emacs "26.1") (dash "2.13") (dash-functional "1.2.0") (org "9.0") (org-super-agenda "1.2-pre") (ov "1.0.6") (peg "0.6") (s "1.12.0") (ts "0.2-pre"))
 ;; Keywords: hypermedia, outlines, Org, agenda
 
@@ -44,17 +44,6 @@
 (require 'dash-functional)
 (require 'ts)
 
-;;;; Compatibility
-
-(if (version< org-version "9.2")
-    (progn
-      (defalias 'org-timestamp-to-time #'org-timestamp--to-internal-time)
-      (defun org-ql--get-tags (&optional pos local)
-        (org-get-tags-at pos local)))
-  (defun org-ql--get-tags (&rest _ignore)
-    "Call `org-get-tags', ignoring arguments."
-    (org-get-tags)))
-
 ;;;; Constants
 
 ;; Note the use of the `rx' `blank' keyword, which matches "horizontal" whitespace.
@@ -76,6 +65,13 @@ match group.")
   "Regular expression matching Org \"planning\" lines.
 That is, \"CLOSED:\", \"DEADLINE:\", or \"SCHEDULED:\".")
 
+(defconst org-ql-tag-line-re
+  "^\\*+ \\(?:.*[ \t]\\)?\\(:\\([[:alnum:]_@#%:]+\\):\\)[ \t]*$"
+  ;; Copied from `org-tag-line-re' from org.el.
+  "Regexp matching tags in a headline.
+Tags are stored in match group 1.  Match group 2 stores the tags
+without the enclosing colons.")
+
 ;;;; Variables
 
 (defvar org-ql--today nil)
@@ -383,7 +379,8 @@ Returns cons (INHERITED-TAGS . LOCAL-TAGS)."
         ('org-ql-nil nil)
         (_ cached-result))
     ;; Not found in cache: get tags and cache them.
-    (let* ((local-tags (or (org-ql--get-tags position 'local)
+    (let* ((local-tags (or (when (looking-at org-ql-tag-line-re)
+                             (split-string (match-string-no-properties 2) ":" t))
                            'org-ql-nil))
            (inherited-tags (or (when org-use-tag-inheritance
                                  (save-excursion