diff --git a/configure.ac b/configure.ac
index e46f8d52..ce86e6f6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -146,7 +146,6 @@ if test "x$ac_cv_debugging" = "xyes"; then
     fi
 
     AC_DEFINE([ENABLE_DEBUGGING], [], [Description])
-    AC_DEFINE([_FORTIFY_SOURCE], [2], [Description])
     AC_DEFINE([_GLIBCXX_DEBUG], [], [Description])
 
 else