New functions: at-exit-call and at-exit-do-not-call.

* sysif.c (at_exit_list): New static variable.
(at_exit_call, at_exit_do_not_call): New functions.
(at_exit_handler): New static function.
(sysif_init): GC-protect at_exit_list.
Register at_exit_handler with C atexit function.
Register intrinsic functions at-exit-call and
at-exit-do-not-call.

* sysif.h (at_exit_call, at_exit_do_not_call): Registered.

* txr.1: Documented.

1 files changed, 2 insertions, 0 deletions

diff --git a/sysif.h b/sysif.h
index 62712387..5b22ea5c 100644
--- a/sysif.h
+++ b/sysif.h
@@ -43,6 +43,8 @@ typedef long off_t;
 #endif
 
 val getenv_wrap(val name);
+val at_exit_call(val func);
+val at_exit_do_not_call(val func);
 #if HAVE_FORK_STUFF
 val exec_wrap(val file, val args_opt);
 #endif