Fix missing include
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/tests/suites/test_suite_ctr_drbg.function b/tests/suites/test_suite_ctr_drbg.function
index 0f1237c..7123d14 100644
--- a/tests/suites/test_suite_ctr_drbg.function
+++ b/tests/suites/test_suite_ctr_drbg.function
@@ -3,6 +3,10 @@
#include "mbedtls/ctr_drbg.h"
#include "string.h"
+#if defined(MBEDTLS_THREADING_PTHREAD)
+#include "mbedtls/threading.h"
+#endif
+
/* Modes for ctr_drbg_validate */
enum reseed_mode {
RESEED_NEVER, /* never reseed */