lib: don't GC-protect two non-heap objects.

* lib.c (obj_init): The null string literal and "nil" do not
require gc protection; they cannot be reclaimed by the garbage
collector, which ignores them. Don't waste two slots in the
prot_stack on them. This is a remnant from ancient TXR;
these variables were protected already in Version 11 from
September 2009. At that time, there were no built-in string
literal objects; these two objects were heap-allocated.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib.c b/lib.c
index 08b84c74..f08c7949 100644
--- a/lib.c
+++ b/lib.c
@@ -10765,7 +10765,7 @@ static void obj_init(void)
    */
 
   protect(&packages, &system_package, &keyword_package,
-          &user_package, &public_package, &null_string, &nil_string,
+          &user_package, &public_package,
           &null_list, &equal_f, &eq_f, &eql_f,
           &car_f, &cdr_f, &null_f, &list_f,
           &identity_f, &less_f, &greater_f, &prog_string, &env_list,