Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/build/feature/test-gettid.c b/tools/build/feature/test-gettid.c
new file mode 100644
index 0000000..ef24e42
--- /dev/null
+++ b/tools/build/feature/test-gettid.c
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2019, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
+#define _GNU_SOURCE
+#include <unistd.h>
+
+int main(void)
+{
+	return gettid();
+}
+
+#undef _GNU_SOURCE