An independent .m4 file for each module.

[gnulib.git] / m4 / dirfd.m4

diff --git a/m4/dirfd.m4 b/m4/dirfd.m4
index 7f52bf3..27914de 100644 (file)
--- a/m4/dirfd.m4
+++ b/m4/dirfd.m4
@@ -1,10 +1,14 @@
-#serial 1
+#serial 3
 
 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
@@ -25,25 +29,35 @@ 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,$jm_cv_func_dirfd_macro \
+      = no,no,no; then
     AC_REPLACE_FUNCS([dirfd])
     AC_CACHE_CHECK(
              [how to get the file descriptor associated with an open DIR*],
                   ac_cv_sys_dir_fd_member_name,
       [
-        dirfd_save_DEFS=$DEFS
+        dirfd_save_CFLAGS=$CFLAGS
        for ac_expr in d_fd dd_fd; do
 
-         DEFS="$DEFS -DDIR_FD_MEMBER_NAME=$ac_expr"
+         CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
          AC_TRY_COMPILE(
            [$dirfd_headers
            ],
            [DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;],
            dir_fd_found=yes
          )
-         DEFS=$dirfd_save_DEFS
+         CFLAGS=$dirfd_save_CFLAGS
          test "$dir_fd_found" = yes && break
        done
        test "$dir_fd_found" = yes || ac_expr=-1
@@ -58,11 +72,11 @@ AC_DEFUN([UTILS_FUNC_DIRFD],
     fi
     AH_VERBATIM(DIR_TO_FD,
                [#ifdef DIR_FD_MEMBER_NAME
-                # define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
-                #else
-                # define DIR_TO_FD(Dir_p) -1
-                #endif
-                ]
-               )
+# define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
+#else
+# define DIR_TO_FD(Dir_p) -1
+#endif
+]
+    )
   fi
 ])