--- src/lib/libast/sfio/sfcvt.c
+++ src/lib/libast/sfio/sfcvt.c	2008-12-17 11:56:17.000000000 +0000
@@ -56,6 +56,14 @@ static char		*Zero = "0";
 #define _lib_signbit	1
 #endif
 
+#if defined(__ia64__) && defined(signbit)
+# if defined __GNUC__ && __GNUC__ >= 4
+#  define __signbitl(f)	__builtin_signbitl(f)
+# elif _lib_copysignl
+#  define __signbitl(f)	(int)(copysignl(1.0,(f))<0.0)
+# endif
+#endif
+
 #if ! _lib_signbit
 #if ! _ast_fltmax_double
 static int neg0ld(Sfdouble_t f)