Use new documented autoconf macros.

[gnulib.git] / m4 / dirfd.m4

diff --git a/m4/dirfd.m4 b/m4/dirfd.m4
index f18bf80..0e1090e 100644 (file)
--- a/m4/dirfd.m4
+++ b/m4/dirfd.m4
@@ -1,10 +1,14 @@
-#serial 1
+#serial 4
 
 dnl Find out how to get the file descriptor associated with an open DIR*.
 dnl From Jim Meyering
 
 AC_DEFUN([UTILS_FUNC_DIRFD],
 [
+  dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
+  AC_REQUIRE([AC_PROG_CPP])
+  AC_REQUIRE([AC_PROG_EGREP])
+
   AC_HEADER_DIRENT
   dirfd_headers='
 #if HAVE_DIRENT_H
@@ -25,9 +29,19 @@ AC_DEFUN([UTILS_FUNC_DIRFD],
   AC_CHECK_FUNCS(dirfd)
   AC_CHECK_DECLS([dirfd], , , $dirfd_headers)
 
-  # Use the replacement only if we have neither the function
-  # nor a declaration.
-  if test $ac_cv_func_dirfd,$ac_cv_have_decl_dirfd = no,no; then
+  AC_CACHE_CHECK([whether dirfd is a macro],
+    jm_cv_func_dirfd_macro,
+    AC_EGREP_CPP([dirent_header_defines_dirfd], [$dirfd_headers
+#ifdef dirfd
+ dirent_header_defines_dirfd
+#endif],
+      jm_cv_func_dirfd_macro=yes,
+      jm_cv_func_dirfd_macro=no))
+
+  # Use the replacement only if we have no function, macro,
+  # or declaration with that name.
+  if test $ac_cv_func_dirfd,$ac_cv_have_decl_dirfd,$jm_cv_func_dirfd_macro \
+      = no,no,no; then
     AC_REPLACE_FUNCS([dirfd])
     AC_CACHE_CHECK(
              [how to get the file descriptor associated with an open DIR*],
@@ -51,7 +65,7 @@ AC_DEFUN([UTILS_FUNC_DIRFD],
        ac_cv_sys_dir_fd_member_name=$ac_expr
       ]
     )
-    if test $ac_cv_have_decl_dirfd = -1; then
+    if test $ac_cv_have_decl_dirfd = no; then
       AC_DEFINE_UNQUOTED(DIR_FD_MEMBER_NAME,
        $ac_cv_sys_dir_fd_member_name,
        [the name of the file descriptor member of DIR])