patch 8.1.1497: accessing memory beyond allocated space

Problem:    Accessing memory beyond allocated space.
Solution:   Check column before accessing popup mask.

src/screen.c

@@ -6797,14 +6797,18 @@ screen_line(
     if (clear_width > 0
 #ifdef FEAT_TEXT_PROP
 	    && !(flags & SLF_POPUP)  // no separator for popup window
-	    && popup_mask[row * screen_Columns + col + coloff] <= screen_zindex
 #endif
 	    )
     {
 	// For a window that has a right neighbor, draw the separator char
-	// right of the window contents.
+	// right of the window contents.  But not on top of a popup window.
 	if (coloff + col < Columns)
 	{
+#ifdef FEAT_TEXT_PROP
+	    if (popup_mask[row * screen_Columns + col + coloff]
+							     <= screen_zindex)
+#endif
+	    {
 		int c;
 
 		c = fillchar_vsep(&hl);
@@ -6828,6 +6832,7 @@ screen_line(
 		    screen_char(off_to, row, col + coloff);
 		}
 	    }
+	}
 	else
 	    LineWraps[row] = FALSE;
     }

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1497,
 /**/
     1496,
 /**/