Requiring grep which supports multiple -e options

[Stepan Kasal]

Hello all,
  it was brought to my attention that virtually every Autoconf
generated script calls AC_PROG_GREP.

(The call stack imay look like this:
AC_CHECK_HEADER calls AC_INCLUDES_DEFAULT([]), which
calls AC_HEADER_STDC, which calls AC_EGREP_HEADER, AC_EGREP_CPP,
AC_PROG_EGREP, AC_PROG_GREP.)

But AC_PROG_GREP wants grep which supports multiple -e options and
stops with an error if there is none available.
Is that requirement really necessary?  Does a "usual" configure
script really need it?

If not, could this requirement be relaxed somehow?

The reporter has actually expirienced this when building GNU grep on
LunxOS.  (Well, I can only guess that he tried to build GNU grep
because another configure script has told him that none of the
supplied grep binaries is usable.  ;-)

In case the requirements for grep are not relaxed in Autoconf itself,
shouldn't GNU grep contain a workaround, eg. a modified definition of
AC_PROG_GREP?

See: http://savannah.gnu.org/bugs/?22818
(I closed it as wontfix, but I still think a short discussion about
this topic might be useful.)

Cheers,
        Stepan Kasal