debug_check calls are the culprit triggering lookahead

in lazy lists. Changing the semantics of the data argument
so that it can just be the list.

* debug.c (debug): If data is a cons, then replace it with
the first item.

* match.c (match_files): Pass c.data to debug_check, rather
than the value of if2(consp(c.data), car(c.data)) which accesses
car(c.data) whether or not we are debugging.
(match_fun): Likewise.

1 files changed, 2 insertions, 0 deletions

diff --git a/debug.c b/debug.c
index fa7c439e..ec754874 100644
--- a/debug.c
+++ b/debug.c
@@ -92,6 +92,8 @@ val debug(val form, val bindings, val data, val line, val pos, val base)
   val loc = source_loc(form);
   cons_bind (lineno, file, loc);
 
+  data = if2(consp(data), car(data));
+
   if (!step_mode && !memqual(loc, breakpoints) 
       && (debug_depth > next_depth))
   {