diff --git a/configure b/configure
index 9a41d15..cde0e17 100755
--- a/configure
+++ b/configure
@@ -376,6 +376,13 @@ case $SYSTEM in
     ;;
 esac
 
+if test_code '64-bit time_t' 'time.h' '' '' '
+  char x[sizeof(time_t) > 4 ? 1 : -1] = {0};
+  return x[0];'
+then
+  add_def HAVE_LONG_TIME_T 1
+fi
+
 MATHCODE='return (int) pow(2.0, log(sqrt((double)argc)));'
 if test_code 'math' 'math.h' '' '' "$MATHCODE"; then
   LIBS=""