diff --git a/configure b/configure
index e2b37af..8c46079 100755
--- a/configure
+++ b/configure
@@ -682,6 +682,20 @@ fi
 
 rm -f $TESTO $TESTP
 
+#
+#  size of select fd_set
+#
+TESTC=config/fdset.c
+size_fdset=128
+echo $ac_n "checking size of select fd_set ... "$ac_c
+$CC -o $TESTP $TESTC 1> /dev/null 2> /dev/null
+if [ -x $TESTP ]; then
+  size_fdset=`$TESTP`
+fi
+echo $ac_t "$size_fdset bytes"
+
+rm -f $TESTP
+
 #
 #  32bit? 64bit?
 #
@@ -695,7 +709,11 @@ if [ -z "$ptr_size" ]; then
   if [ -x $TESTP ]; then
     ptr_size=`$TESTP`
   fi
-  echo $ac_t "$ptr_size"
+  if [ "$ptr_size" = 8 ]; then
+    echo $ac_t "64 bit"
+  else
+    echo $ac_t "$ptr_size"
+  fi
 fi
 
 case _"$ptr_size"_ in