diff --git a/configure.ac b/configure.ac
index cb1fdfd..71c0515 100644
--- a/configure.ac
+++ b/configure.ac
@@ -771,7 +771,7 @@
  
 if test "$psize" = "0"; then
     psizer=`getconf PAGESIZE`
-    let "psize=${psizer}/1024"
+    psize=$((${psizer}/1024))
 fi
 
 if test "$psize" = "4"; then