diff --git a/ap/libc/glibc/glibc-2.23/signal/sigaltstack.c b/ap/libc/glibc/glibc-2.23/signal/sigaltstack.c
new file mode 100644
index 0000000..34e3545
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.23/signal/sigaltstack.c
@@ -0,0 +1,30 @@
+/* Copyright (C) 1992-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <signal.h>
+
+/* Run signals handlers on the stack specified by SS (if not NULL).
+   If OSS is not NULL, it is filled in with the old signal stack status.  */
+int
+sigaltstack (const struct sigaltstack *ss, struct sigaltstack *oss)
+{
+  __set_errno (ENOSYS);
+  return -1;
+}
+
+stub_warning (sigaltstack)