Re: _AS_ECHO_N_PREPARE - bug correction in ksh88 on AIX 6.1

[Ralf Wildenhues]

Hi Jan,

* Jan Madzik wrote on Thu, Jun 25, 2009 at 06:48:37PM CEST:
> I found bug in korn shell (version M-11/16/88f) on AIX 6.1 (tested
> only on one server instance) and due to this bug I couldn't correctly
> configure ImageMagick.

Confirmed on AIX 5.3, thanks for the bug report.

This patch should be sufficient to fix this instance of the bug, but
it's still lacking a testsuite and documentation addition.

Cheers,
Ralf

diff --git a/lib/m4sugar/m4sh.m4 b/lib/m4sugar/m4sh.m4
index c7b0bff..162b780 100644
--- a/lib/m4sugar/m4sh.m4
+++ b/lib/m4sugar/m4sh.m4
@@ -780,12 +780,13 @@ m4_defun_init([_AS_ECHO_LOG],
 # display the checking message.  In addition, caching something used once
 # has little interest.
 # Idea borrowed from dist 3.0.  Use `*c*,', not `*c,' because if `\c'
-# failed there is also a newline to match.
+# failed there is also a newline to match.  Add another echo after echoing
+# `\c' in a command substitution to reset a ksh88 bug on AIX 6.1.
 m4_defun([_AS_ECHO_N_PREPARE],
 [ECHO_C= ECHO_N= ECHO_T=
 case `echo -n x` in @%:@((((
 -n*)
-  case `echo 'x\c'` in
+  case `echo 'x\c'; echo` in
   *c*) ECHO_T='        ';;     # ECHO_T is single tab character.
   *)   ECHO_C='\c';;
   esac;;