LibC: Add public and independent ucontext.h header

Author: https://github.com/ADKaster
Commit: https://github.com/SerenityOS/serenity/commit/6ef355739d
Pull-request: https://github.com/SerenityOS/serenity/pull/14260
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibC/ucontext.h

@@ -0,0 +1,9 @@
+/*
+ * Copyright (c) 2022, Andrew Kaster <akaster@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <Kernel/API/POSIX/ucontext.h>