Even 'gshadow' meson option is disabled, src/shared/userdb.c and
src/shared/user-record-nss.c include gshadow.h unconditionally.
Let's introduce dummy header to make them compiled gracefully.
--- /dev/null
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <errno.h>
+#include <stddef.h>
+
+struct sgrp {
+ char *sg_namp;
+ char *sg_passwd;
+ char **sg_adm;
+ char **sg_mem;
+};
+
+static inline int getsgnam_r(
+ const char *__name,
+ struct sgrp *__result_buf,
+ char *__buffer,
+ size_t __buflen,
+ struct sgrp **__result) {
+
+ return EOPNOTSUPP; /* this function returns positive errno in case of error. */
+}