Fix DEBUGGING detection in t/run/todo.t

326f023 did not account for the fact
that one can say -DDEBUGGING=none to mean no debugging.  This checks for
that.

Author: khwilliamson

t/run/todo.t

@@ -103,7 +103,7 @@ use warnings;
 
 my $switches = "";
 
-my $is_debugging_build = $Config{config_args} =~ /\bDDEBUGGING\b/;
+my $is_debugging_build = $Config{config_args} =~ /\bDDEBUGGING\b(*nla:=none)/;
 
 our $TODO;