diff --git a/src/m/ibmrt-aix.h b/src/m/ibmrt-aix.h
index 2ec5919a280..83f122051c4 100644
--- a/src/m/ibmrt-aix.h
+++ b/src/m/ibmrt-aix.h
@@ -178,3 +178,6 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 
 /* AIX defines FIONREAD, but it does not work.  */
 #define BROKEN_FIONREAD
+
+/* rocky@watson.ibm.com says this is needed.  */
+#define HAVE_FTIME