diff --git a/configure.ac b/configure.ac
index fdb33a58f1950257183d9e7c33f68972d757d030..6ac6ba41ad2857a0939499ce6faeed2f8c2423e9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -970,7 +970,8 @@ AC_HELP_STRING([--disable-ares],[Disable using ares for name lookups]),
          AC_MSG_ERROR([ares doesn't work with ipv6, disable ipv6 to use ares])
        fi
 
-       CPPFLAGS="$CPPFLAGS -DUSE_ARES"
+       AC_DEFINE(USE_ARES, 1, [Define if you want to enable ares support])
+
        ares="yes"
        ;;
   esac ],