updated for version 7.3.893
Problem:    Crash when using b:, w: or t: after closing the buffer, window or
            tabpage.
Solution:   Allocate the dictionary instead of having it part of the
            buffer/window/tabpage struct. (Yukihiro Nakadaira)
diff --git a/src/structs.h b/src/structs.h
index 36440c3..6305129 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1611,7 +1611,7 @@
 
 #ifdef FEAT_EVAL
     dictitem_T	b_bufvar;	/* variable for "b:" Dictionary */
-    dict_T	b_vars;		/* internal variables, local to buffer */
+    dict_T	*b_vars;	/* internal variables, local to buffer */
 #endif
 
 #if defined(FEAT_BEVAL) && defined(FEAT_EVAL)
@@ -1757,7 +1757,7 @@
     frame_T	    *(tp_snapshot[SNAP_COUNT]);  /* window layout snapshots */
 #ifdef FEAT_EVAL
     dictitem_T	    tp_winvar;	    /* variable for "t:" Dictionary */
-    dict_T	    tp_vars;	    /* internal variables, local to tab page */
+    dict_T	    *tp_vars;	    /* internal variables, local to tab page */
 #endif
 };
 
@@ -2080,7 +2080,7 @@
 
 #ifdef FEAT_EVAL
     dictitem_T	w_winvar;	/* variable for "w:" Dictionary */
-    dict_T	w_vars;		/* internal variables, local to window */
+    dict_T	*w_vars;	/* internal variables, local to window */
 #endif
 
 #if defined(FEAT_RIGHTLEFT) && defined(FEAT_FKMAP)