‣ merge from mksh R40-stable

document the unportability of the echo utility;
arekm's non-bug report inspired this

mksh.1

@@ -1,4 +1,4 @@
-.\" $MirOS: src/bin/mksh/mksh.1,v 1.269 2011/07/07 21:24:53 tg Exp $
+.\" $MirOS: src/bin/mksh/mksh.1,v 1.270 2011/07/16 17:07:48 tg Exp $
 .\" $OpenBSD: ksh.1,v 1.140 2011/04/23 10:14:59 sobrado Exp $
 .\"-
 .\" Copyright © 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
@@ -72,7 +72,7 @@
 .\" with -mandoc, it might implement .Mx itself, but we want to
 .\" use our own definition. And .Dd must come *first*, always.
 .\"
-.Dd $Mdocdate: July 7 2011 $
+.Dd $Mdocdate: July 16 2011 $
 .\"
 .\" Check which macro package we use
 .\"
@@ -3235,6 +3235,13 @@ defaults to 1.
 .Op Fl Een
 .Op Ar arg ...
 .Xc
+.Em Warning:
+this utility is not portable; use the Korn shell builtin
+.Ic print
+or the much slower POSIX utility
+.Ic printf
+instead.
+.Pp
 Prints its arguments (separated by spaces) followed by a newline, to the
 standard output.
 The newline is suppressed if any of the arguments contain the
@@ -3627,7 +3634,7 @@ option suppresses the trailing newline.
 .It Ic printf Ar format Op Ar arguments ...
 Formatted output.
 Approximately the same as the utility
-.Xr printf 1 ,
+.Ic printf ,
 except that it uses the same
 .Sx Backslash expansion
 and I/O code as the rest of
@@ -6127,6 +6134,7 @@ Privileged shell profile.
 .Xr cat 1 ,
 .Xr ed 1 ,
 .Xr getopt 1 ,
+.Xr printf 1 ,
 .Xr sed 1 ,
 .Xr sh 1 ,
 .Xr stty 1 ,