patch 7.4.1735
Problem:    It is not possible to only see part of the message history.  It is
            not possible to clear messages.
Solution:   Add a count to ":messages" and a clear argument. (Yasuhiro
            Matsumoto)
diff --git a/src/ex_cmds.h b/src/ex_cmds.h
index 34defea..4095331 100644
--- a/src/ex_cmds.h
+++ b/src/ex_cmds.h
@@ -886,7 +886,7 @@
 			EXTRA|TRLBAR|NOTRLCOM|USECTRLV|CMDWIN,
 			ADDR_LINES),
 EX(CMD_messages,	"messages",	ex_messages,
-			TRLBAR|CMDWIN,
+			EXTRA|TRLBAR|RANGE|CMDWIN,
 			ADDR_LINES),
 EX(CMD_mkexrc,		"mkexrc",	ex_mkrc,
 			BANG|FILE1|TRLBAR|CMDWIN,