diff --git a/indra/llmath/llvector4a.h b/indra/llmath/llvector4a.h
index f5bb54065606980ee70ca8cc859bef33d84843e0..043a59a750af19d62920e04456b7a0e0a77b0547 100644
--- a/indra/llmath/llvector4a.h
+++ b/indra/llmath/llvector4a.h
@@ -60,8 +60,10 @@ class LLVector4a
 	// Call initClass() at startup to avoid 15,000+ cycle penalties from denormalized numbers
 	static void initClass()
 	{
+#if LL_WINDOWS
 		unsigned int current_word = 0;
 		_controlfp_s(&current_word, _DN_FLUSH, _MCW_DN);
+#endif
 		_MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_ON);
 		_MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
 		_MM_SET_ROUNDING_MODE(_MM_ROUND_NEAREST);