diff --git a/package/optee-client/0001-libckteec-add-missing-unistd.h-for-gid_t.patch b/package/optee-client/0001-libckteec-add-missing-unistd.h-for-gid_t.patch
new file mode 100644
index 0000000000..534f1d3bee
--- /dev/null
+++ b/package/optee-client/0001-libckteec-add-missing-unistd.h-for-gid_t.patch
@@ -0,0 +1,31 @@
+From 6b908687d37dc4e5c00df90058990da034506628 Mon Sep 17 00:00:00 2001
+From: Etienne Carriere <etienne.carriere@linaro.org>
+Date: Tue, 9 Mar 2021 11:52:32 +0100
+Subject: [PATCH 1/1] libckteec: add missing <unistd.h> for gid_t
+
+Include missing unistd.h to support type gid_t. This change fixes [1].
+
+Link: [1] http://autobuild.buildroot.net/results/34b9946e6d59112a7eead304933534ad4739a84c/build-end.log
+Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
+Acked-by: Jerome Forissier <jerome@forissier.org>
+[yann.morin.1998@free.fr: actual backport now that upstream applied it]
+Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
+---
+ libckteec/src/invoke_ta.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/libckteec/src/invoke_ta.c b/libckteec/src/invoke_ta.c
+index 6236719..70575d0 100644
+--- a/libckteec/src/invoke_ta.c
++++ b/libckteec/src/invoke_ta.c
+@@ -18,6 +18,7 @@
+ #include <sys/types.h>
+ #include <tee_client_api.h>
+ #include <teec_trace.h>
++#include <unistd.h>
+ 
+ #include "ck_helpers.h"
+ #include "invoke_ta.h"
+-- 
+2.25.1
+