--- a/configure.ac
+++ b/configure.ac
@@ -25,6 +25,10 @@
     AC_DEFINE([STRESSAPPTEST_CPU_I686],[],
               [Defined if the target CPU is i686])
     ;;
+  "xi586"*)
+    AC_DEFINE([STRESSAPPTEST_CPU_I686],[],
+              [Defined if the target CPU is i586])
+    ;;
   "xi486"*)
     AC_DEFINE([STRESSAPPTEST_CPU_I686],[],
               [Defined if the target CPU is i486])
