adl_func_getopt_long

Check for getopt_long support.

This assume that the standard getopt.h file (from GNU libc) is available as lib/gnugetopt.h. If needed, this file will be linked as getopt.h, but we want to default to the system's getopt.h file. (See http://sources.redhat.com/ml/automake/2000-09/msg00041.html for an explanation about why using the system's getopt.h file is important.)

AC_DEFUN([adl_FUNC_GETOPT_LONG],
 [AC_PREREQ(2.49)dnl
  # clean out junk possibly left behind by a previous configuration
  rm -f lib/getopt.h
  # Check for getopt_long support
  AC_CHECK_HEADERS([getopt.h])
  AC_CHECK_FUNCS([getopt_long],,
   [# FreeBSD has a gnugetopt library for this
    AC_CHECK_LIB([gnugetopt],[getopt_long],[AC_DEFINE([HAVE_GETOPT_LONG])],
     [# use the GNU replacement
      AC_LIBOBJ(getopt)
      AC_LIBOBJ(getopt1)
      AC_CONFIG_LINKS([lib/getopt.h:lib/gnugetopt.h])])])])