libpayload: Add <stdbool.h>

Change-Id: I972c78c5da4136bc61e78fcbb52d7d162cc1b698
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46721
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

payloads/libpayload/include/stdbool.h

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+
+#ifndef __STDBOOL_H
+#define __STDBOOL_H
+
+#define bool	_Bool
+#define false	0
+#define true	(!false)
+
+#endif