diff --git a/indra/llmath/llmatrix3a.cpp b/indra/llmath/llmatrix3a.cpp
index ab077abcb..ad008e9d3 100644
--- a/indra/llmath/llmatrix3a.cpp
+++ b/indra/llmath/llmatrix3a.cpp
@@ -24,6 +24,7 @@
  * $/LicenseInfo$
  */
 
+#include "sys.h"
 #include "llmath.h"
 
 static LL_ALIGN_16(const F32 M_IDENT_3A[12]) =