Fix bug in error handling where __sub would be clobbered.
diff --git a/src/lisp/lib/std.c b/src/lisp/lib/std.c
index 5ad02bc..0a203b5 100644
--- a/src/lisp/lib/std.c
+++ b/src/lisp/lib/std.c
@@ -97,7 +97,7 @@
 	struct istream *is = new_stristream_nt(string);
 
 	value_t val = nil;
-	struct error err;
+	struct error err = { 0 };
 	
 	if (!IS_OKAY((err = read1(is, &val))))
 	{