Backport commit 98288ecaf from Emacs

* lisp/org-clock.el (org-clock--oldest-date): Fix an issue when
compiling on macOS 10.6 with a western time zone (a continuation of
Bug#27736).

Further workaround for faulty localtime() under macOS 10.6
98288ecaffbc0947ec3193088172ea85ad5e42a5
Charles A. Roelli
Wed Nov 8 20:51:48 2017 +0100

lisp/org-clock.el

@@ -487,7 +487,7 @@ to add an effort property.")
                                    "10\\.6\\.[[:digit:]]"
                                    (shell-command-to-string
                                     "sw_vers -productVersion"))
-                                  (<= m -1034058203136))
+                                  (<= m -1034058203135))
                        (ignore-errors (decode-time (list m 0)))))))
 	 (low
 	  (funcall dichotomy