Only define test_hooks_xxx under MBEDTLS_TEST_HOOKS

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index ef804c9..d0758bc 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -734,7 +734,9 @@
     mbedtls_memory_buffer_alloc_init( alloc_buf, sizeof(alloc_buf) );
 #endif
 
+#if defined(MBEDTLS_TEST_HOOKS)
     test_hooks_init( );
+#endif /* MBEDTLS_TEST_HOOKS */
 
     /*
      * Make sure memory references are valid.
@@ -3042,6 +3044,7 @@
     mbedtls_psa_crypto_free( );
 #endif
 
+#if defined(MBEDTLS_TEST_HOOKS)
     if( test_hooks_failure_detected( ) )
     {
         if( ret == 0 )
@@ -3049,6 +3052,7 @@
         mbedtls_printf( "Test hooks detected errors.\n" );
     }
     test_hooks_free( );
+#endif /* MBEDTLS_TEST_HOOKS */
 
 #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
 #if defined(MBEDTLS_MEMORY_DEBUG)