Implement finalizers for module functions (Bug#30373)

* src/module-env-28.h: Add new module environment functions to
module environment for Emacs 28.

* src/emacs-module.h.in: Document that 'emacs_finalizer' also works
for function finalizers.

* src/emacs-module.c (CHECK_MODULE_FUNCTION): New function.
(struct Lisp_Module_Function): Add finalizer data member.
(module_make_function): Initialize finalizer.
(module_get_function_finalizer)
(module_set_function_finalizer): New module environment functions.
(module_finalize_function): New function.
(initialize_environment): Initialize new environment functions.

* src/alloc.c (cleanup_vector): Call potential module function
finalizer during garbage collection.

* test/data/emacs-module/mod-test.c (signal_error): New helper
function.
(memory_full): Use it.
(finalizer): New example function finalizer.
(Fmod_test_make_function_with_finalizer)
(Fmod_test_function_finalizer_calls): New test module functions.
(emacs_module_init): Define them.

* test/src/emacs-module-tests.el (module/function-finalizer): New unit
test.

* doc/lispref/internals.texi (Module Functions): Document new
functionality.
(Module Misc): Move description of 'emacs_finalizer' type to 'Module
Functions' node, and add a reference to it.

* etc/NEWS: Mention new functionality.

1 files changed, 5 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index df12c7e8430..d6cabf8e9e4 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -49,6 +49,11 @@ applies, and please also update docstrings as needed.
 'emacs_function' and 'emacs_finalizer' for module functions and
 finalizers, respectively.
 
+** Module functions can now install an optional finalizer that is
+called when the function object is garbage-collected.  Use
+'set_function_finalizer' to set the finalizer and
+'get_function_finalizer' to retrieve it.
+
 
 * Changes in Emacs 28.1 on Non-Free Operating Systems