diff --git a/Pal/src/host/Linux-SGX/debugger/sgx_gdb.c b/Pal/src/host/Linux-SGX/debugger/sgx_gdb.c
index 9526d771..9938813d 100644
--- a/Pal/src/host/Linux-SGX/debugger/sgx_gdb.c
+++ b/Pal/src/host/Linux-SGX/debugger/sgx_gdb.c
@@ -1,6 +1,7 @@
 /* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */
 /* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */
 
+#define _GNU_SOURCE
 #include <stddef.h>
 #include <unistd.h>
 #include <stdio.h>