port: Add alternative for isinf.
diff --git a/configure b/configure
index 87a5a17..2f1f1ca 100755
--- a/configure
+++ b/configure
@@ -21233,6 +21233,66 @@
fi
+{ echo "$as_me:$LINENO: checking for isinf" >&5
+echo $ECHO_N "checking for isinf... $ECHO_C" >&6; }
+if test "${ac_cv_have_isinf+set}" = set; then
+ echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+ cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h. */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h. */
+#include <math.h>
+int
+main ()
+{
+float f = 0.0; isinf(f)
+ ;
+ return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+ *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+ *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+ (eval "$ac_link") 2>conftest.er1
+ ac_status=$?
+ grep -v '^ *+' conftest.er1 >conftest.err
+ rm -f conftest.er1
+ cat conftest.err >&5
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); } && {
+ test -z "$ac_c_werror_flag" ||
+ test ! -s conftest.err
+ } && test -s conftest$ac_exeext &&
+ $as_test_x conftest$ac_exeext; then
+ ac_cv_have_isinf="yes"
+else
+ echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ ac_cv_have_isinf="no"
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+ conftest$ac_exeext conftest.$ac_ext
+fi
+{ echo "$as_me:$LINENO: result: $ac_cv_have_isinf" >&5
+echo "${ECHO_T}$ac_cv_have_isinf" >&6; }
+if test "$ac_cv_have_isinf" = "yes"
+then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_ISINF 1
+_ACEOF
+
+fi
+
case $host_cpu in
*i[3456789]86*) { echo "$as_me:$LINENO: checking whether we need to define __i386__" >&5
