(UTILS_FUNC_DIRFD): Rework so dirfd.c doesn't have to

know the name of the variable in the macro definition.

diff --git a/m4/dirfd.m4 b/m4/dirfd.m4
index 9b6fb45..7f52bf3 100644 (file)
--- a/m4/dirfd.m4
+++ b/m4/dirfd.m4
@@ -31,38 +31,38 @@ AC_DEFUN([UTILS_FUNC_DIRFD],
     AC_REPLACE_FUNCS([dirfd])
     AC_CACHE_CHECK(
              [how to get the file descriptor associated with an open DIR*],
-                  ac_cv_sys_dir_to_fd,
+                  ac_cv_sys_dir_fd_member_name,
       [
         dirfd_save_DEFS=$DEFS
-       for ac_expr in                                          \
-                                                               \
-           'dir_p->d_fd'                                       \
-                                                               \
-           'dir_p->dd_fd'                                      \
-                                                               \
-           '# systems for which the info is not available'     \
-           -1                                                  \
-           ; do
+       for ac_expr in d_fd dd_fd; do
 
-         # Skip each embedded comment.
-         case "$ac_expr" in '#'*) continue;; esac
-
-         DEFS="$DEFS -DDIR_TO_FD=$ac_expr"
+         DEFS="$DEFS -DDIR_FD_MEMBER_NAME=$ac_expr"
          AC_TRY_COMPILE(
            [$dirfd_headers
            ],
-           [DIR *dir_p = opendir("."); (void) ($ac_expr);],
-           dir_fd_done=yes
+           [DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;],
+           dir_fd_found=yes
          )
          DEFS=$dirfd_save_DEFS
-         test "$dir_fd_done" = yes && break
+         test "$dir_fd_found" = yes && break
        done
+       test "$dir_fd_found" = yes || ac_expr=-1
 
-       ac_cv_sys_dir_to_fd=$ac_expr
+       ac_cv_sys_dir_fd_member_name=$ac_expr
       ]
     )
-    AC_DEFINE_UNQUOTED(DIR_TO_FD,
-      $ac_cv_sys_dir_to_fd,
-      [the file descriptor associated with `dir_p'])
+    if test $ac_cv_have_decl_dirfd = -1; then
+      AC_DEFINE_UNQUOTED(DIR_FD_MEMBER_NAME,
+       $ac_cv_sys_dir_fd_member_name,
+       [the name of the file descriptor member of DIR])
+    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
+                ]
+               )
   fi
 ])