diff --git a/nonlib/JACK/Client.C b/nonlib/JACK/Client.C
index 7bae8f1..9cc1375 100644
--- a/nonlib/JACK/Client.C
+++ b/nonlib/JACK/Client.C
@@ -115,7 +115,7 @@ namespace JACK
     void
     Client::thread_init ( void *arg )
     {
-#if __SSE2_MATH__
+#ifdef __SSE2_MATH__
     /* set FTZ and DAZ flags */
     _mm_setcsr(_mm_getcsr() | 0x8040);
 #endif