base: Do support /dev/null as a config file

lib/base/config_file.c

@@ -535,6 +535,22 @@ heim_config_parse_dir_multi(heim_context context,
     return 0;
 }
 
+static int
+is_devnull(struct stat *st)
+{
+#ifdef WIN32
+    return 0;
+#else
+    struct stat devnullst;
+
+    if (stat("/dev/null", &devnullst) == -1)
+        return 0;
+    return st->st_dev == devnullst.st_dev && st->st_ino == devnullst.st_ino;
+#endif
+}
+
+HEIMDAL_THREAD_LOCAL int config_include_depth = 0;
+
 /**
  * Parse a configuration file and add the result into res. This
  * interface can be used to parse several configuration files into one
@@ -548,8 +564,6 @@ heim_config_parse_dir_multi(heim_context context,
  * @ingroup heim_support
  */
 
-HEIMDAL_THREAD_LOCAL int config_include_depth = 0;
-
 heim_error_code
 heim_config_parse_file_multi(heim_context context,
                              const char *fname,
@@ -630,7 +644,7 @@ heim_config_parse_file_multi(heim_context context,
             goto out;
         }
 
-        if (!S_ISREG(st.st_mode)) {
+        if (!S_ISREG(st.st_mode) && !is_devnull(&st)) {
             (void) fclose(f.f);
             heim_set_error_message(context, EISDIR, "not a regular file %s: %s",
                                    fname, strerror(EISDIR));