--enable-debug is default.

configure.in

@@ -62,8 +62,8 @@ dnl Debug mode?
 dnl ---------------------------------------------------------------------
 
 AC_ARG_ENABLE(debug,
-[  --enable-debug             enable debug mode [default=no]],
-              , enable_debug=no)
+[  --enable-debug             enable debug mode [default=yes]],
+              , enable_debug=yes)
 if test x$enable_debug = xyes; then
   if test x$ac_cv_prog_cc_g = xyes; then
     CFLAGS="-g -O0"