patch 7.4.1847

Problem:    Getting an item from a NULL dict crashes.  Setting a register to a
            NULL list crashes. (Nikolai Pavlov, issue #768)  Comparing a NULL
            dict with a NULL dict fails.
Solution:   Properly check for NULL.

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1847,
 /**/
     1846,
 /**/