segmentation fault on 'unset MAIL' for bash 2.01.1(1)-release

[Brian Gough]

Hello, 

This has probably been reported before but Autoconf 2.57 produces
configure scripts that immediately segfault on bash in Debian 2.1
(stable).

e.g.   $ ./configure
       Segmentation fault

   bjg|debian>  bash -xv ~/tmp/gsl-1.3.20030729/configure
   #! /bin/sh
   # Guess values for system-dependent variables and create Makefiles.
   # Generated by GNU Autoconf 2.57 for gsl 1.3.20030729.
   ......
   # Work around bugs in pre-3.0 UWIN ksh.
   $as_unset ENV MAIL MAILPATH
   + unset ENV MAIL MAILPATH
   Segmentation fault

   bjg|debian> bash --version
   GNU bash, version 2.01.1(1)-release (i486-pc-linux-gnu)
   Copyright 1997 Free Software Foundation, Inc.

I believe this is a known bug in bash, where 'unset MAIL' triggers a
segfault (see below).  However, since that version of bash is still
quite widely used it would be reasonable for autoconf to avoid
triggering it.

The comment in the autoconf source is "work around bugs in pre-3.0
UWIN ksh".  If this is the only reason I'd suggest removing the unset
command, since it seems to benefit a proprietary OS at the expense of
GNU.

If there is a recommended work-around for GNU packages please let me
know as I am trying to make a new release of GSL (GNU Scientific
Library).  Thanks.

best regards,

-- 
Brian Gough

Network Theory Ltd            
15 Royal Park                 
Bristol BS8 3AL               
United Kingdom                

Tel: +44 (0)117 3179309 
Fax: +44 (0)117 9048108              
Web: http://www.network-theory.co.uk/



bjg|debian> echo $MAIL
/home/bjg/Mail/spool/mail
bjg|debian> cat tmp.sh
#! /bin/sh

unset MAIL

bjg|debian> ./tmp.sh
Segmentation fault