updated for version 7.4a.042

Problem:    Crash when BufUnload autocommands close all buffers. (Andrew
            Pimlott)
Solution:   Set curwin->w_buffer to curbuf to avoid NULL.

src/version.c

@@ -727,6 +727,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    42,
 /**/
     41,
 /**/