AC_SUBST() confuses config.status creation

[Andreas Schwab]

Try this with autoconf >= 2.61a:

$ cat > configure.ac <<EOF
AC_INIT
AC_SUBST()
AC_CONFIG_FILES(Makefile)
AC_OUTPUT
EOF
$ touch Makefile.in
$ autoconf
$ ./configure
configure: creating ./config.status
configure: error: could not make ./config.status

The problem is that $ac_subst_vars contains an empty line and how it is
processed for appending $ac_delim:

  echo "$ac_subst_vars" | sed 's/.*/&!$&$ac_delim/'

An empty line is transformed into $$ac_delim (literally).

While AC_SUBST() is clearly bogus this should probably be handled more
gracefully, perhaps by rejecting it outright.

Andreas.

-- 
Andreas Schwab, SuSE Labs, address@hidden
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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