[Dune] m4 cleanup

[Elias Pipping]

On Fri, Sep 11, 2009 at 1:55 PM, Christian Engwer <christi at uni-hd.de> wrote:
> Hi Elias,
>
> Let me pick out one example:
>
>> -  if test "x$with_hostid" = "xno" ; then
>> -    with_hostid="$ac_hostname (`uname -sm`, $COMPILER_NAME)";
>> -  fi
>> +  AS_IF([test "x$with_hostid" = "xno"],[
>> +    with_hostid="$ac_hostname ($(uname -sm), $COMPILER_NAME)";
>> +  ])
>
> You changed backticks to $(). $() is a bashism and `` is posix-sh. As
> the autotools create a sh-script and not bash I'm a little bit
> surprised. Does automake/autoconf replace these constructions?
> Otherwise I think `` is the safer way to do it. What was the reason
> for this particular change?

Hi,

indeed I forgot that $() are bash- and ksh-only. The problem w/
backticks is that they're special in m4.

  `this is quoted in m4'

As a result, considering e.g.

  dune_griddim.m4:42 variable_griddim="$``(``GRIDDIM``)``"

autom4te refuses to even continue parsing that file:

$ autom4te dune_griddim.m4
/usr/bin/m4:dune_griddim.m4:42: ERROR: end of file in string
autom4te-2.64: /usr/bin/m4 failed with exit status: 1


-- Elias