Re: texindex awk syntax error

[Gavin Smith]

On Mon, Oct 24, 2022 at 08:19:50PM +0200, Bruno Haible wrote:
> does not help here, because nawk and mawk don't implement it. But what
> works, is a test whether $prog supports the function syntax: On this
> platform,
> 
>   gawk 'function foo () {}' 2>/dev/null
>   nawk 'function foo () {}' 2>/dev/null
> 
> both have exit code 0, whereas
> 
>   awk 'function foo () {}' 2>/dev/null
> 
> has exit code 2.
> 
> To implement this, use a variant of AC_CHECK_PROGS that accepts a test
> argument. (AM_PATH_PROG_WITH_TEST from gnulib/m4/progtest.m4 is not the
> right there here, because it searches only for a single program name,
> not multiple ones.)
> 
> Bruno

AC_PATH_PROGS_FEATURE_CHECK does the job although it is slightly complicated
to use:

AC_CACHE_CHECK([for awk], [ac_cv_path_TI_AWK],
    [AC_PATH_PROGS_FEATURE_CHECK([TI_AWK], [awk gawk mawk nawk],
      [[$ac_path_TI_AWK 'function foo () {}' 2>/dev/null \
           && ac_cv_path_TI_AWK=$ac_path_TI_AWK ac_path_TI_AWK_found=:]],
      [AC_MSG_ERROR([awk not found])])])
AC_SUBST([TI_AWK], [$ac_cv_path_TI_AWK])

If this is not going to work we can go back to using AC_CHECK_PROGS with
awk at the front of the list as we shouldn't make the program worse for
the sake of Solaris and/or MS-Windows.