Make _strptime.TimeRE().pattern() use ``\s+`` for matching whitespace instead
of ``\s*``.  This prevents patterns from "stealing" bits from other patterns in
order to make a match work.

Closes bug #1730389.  Will be backported.
diff --git a/Misc/NEWS b/Misc/NEWS
index 562033e..cf61b89 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -222,6 +222,9 @@
 Library
 -------
 
+- Bug #1730389: Change time.strptime() to use ``\s+`` instead of ``\s*`` when
+  matching spaces in the specified format argument.
+
 - SF 1668596/1720897: distutils now copies data files
   even if package_dir is empty.