06-backport-006e66b6680f60adfb434ee7397f0dbc77de7873.patch

diff --git a/configure.in b/configure.in
index 1a001e6..ddc4216 100644
--- a/configure.in
+++ b/configure.in
@@ -1897,6 +1897,7 @@ AC_CHECK_FUNCS(gettimeofday)		# for making ac_cv_func_gettimeofday
 AC_CHECK_FUNCS(gmtime_r)
 AC_CHECK_FUNCS(initgroups)
 AC_CHECK_FUNCS(ioctl)
+AC_CHECK_FUNCS(isfinite)
 AC_CHECK_FUNCS(issetugid)
 AC_CHECK_FUNCS(killpg)
 AC_CHECK_FUNCS(lchmod)
diff --git a/numeric.c b/numeric.c
index 734ab34..f4233d9 100644
--- a/numeric.c
+++ b/numeric.c
@@ -30,8 +30,12 @@
 #include <ieeefp.h>
 #endif
 
+#if !defined HAVE_ISFINITE && !defined isfinite
 #if defined HAVE_FINITE && !defined finite && !defined _WIN32
 extern int finite(double);
+# define HAVE_ISFINITE 1
+# define isfinite(x) finite(x)
+#endif
 #endif
 
 /* use IEEE 64bit values if not defined */
@@ -1457,8 +1461,8 @@ flo_is_finite_p(VALUE num)
 {
     double value = RFLOAT_VALUE(num);
 
-#if HAVE_FINITE
-    if (!finite(value))
+#if HAVE_ISFINITE
+    if (!isfinite(value))
 	return Qfalse;
 #else
     if (isinf(value) || isnan(value))