$OpenBSD: patch-configure,v 1.1 2008/07/25 15:16:34 sthen Exp $
--- configure.orig	Fri Jul 25 15:59:24 2008
+++ configure	Fri Jul 25 16:01:23 2008
@@ -25945,6 +25945,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
+#include <math.h>
 
 /* Override any gcc2 internal prototype to avoid an error.  */
 #ifdef __cplusplus
@@ -25952,13 +25953,12 @@ extern "C"
 #endif
 /* We use char because int might match the return type of a gcc2
    builtin and then its argument prototype would still apply.  */
-char isnan ();
+double val = 0.0;
+
 int
 main ()
 {
-isnan ();
-  ;
-  return 0;
+  return isnan (val);
 }
 _ACEOF
 rm -f conftest.$ac_objext conftest$ac_exeext
