2006-07-20  Claes Wallin  <clacke+guile@lysator.liu.se>

        On Mac OS X 10.4 dirfd is a macro, not a function. This confuces AC_CHECK_FUNCS.
        Use gl_Func_DIRFD from gnulib instead, which does a more thorough check.

        * configure.in:
          Replace AC_CHECK_FUNCS([dirfd]) with gl_FUNC_DIRFD.

        * guile-config/dirfd.m4:
        * libguile/dirfd.c:
        * libguile/dirfd.h:
          Imports from gnulib providing gl_FUNC_DIRFD and associated code.

        * libguile/filesys.c:
          Replace '#define dirfd ...' with '#include "dirfd.h"'

        * test-suite/tests/dirfd.test:
          Since dirfd is used by readdir on platforms that have it, this test
          does an opendir and two consecutive readdirs, expecting "." and "..".
          Not sure if this works on non-posix platforms.