src/comp.c: Use pending_funcalls to fix bug#64494

Make sure `comp.el` is never loaded synchronously by simply
delaying all calls to `native--compile-async` via `pending_funcalls`.

* lisp/startup.el (comp--compilable, comp--delayed-sources): Don't declare.
(startup--require-comp-safely)
(startup--honor-delayed-native-compilations): Delete functions.
(normal-top-level): Don't call `startup--honor-delayed-native-compilations`.

* src/comp.c (maybe_defer_native_compilation): Use `pending_funcalls`.
(syms_of_comp): Delete `Vcomp__delayed_sources` and `comp__compilable`.
Define `Qnative__compile_async`.

lisp/emacs-lisp/comp.el

@@ -4226,6 +4226,7 @@ LOAD and SELECTOR work as described in `native--compile-async'."
                       (string-match-p re file))
                     native-comp-jit-compilation-deny-list))))
 
+;;;###autoload
 (defun native--compile-async (files &optional recursively load selector)
   ;; BEWARE, this function is also called directly from C.
   "Compile FILES asynchronously.

lisp/startup.el

@@ -520,27 +520,6 @@ DIRS are relative."
       xdg-dir)
      (t emacs-d-dir))))
 
-(defvar comp--compilable)
-(defvar comp--delayed-sources)
-(defun startup--require-comp-safely ()
-  "Require the native compiler avoiding circular dependencies."
-  (when (featurep 'native-compile)
-    ;; Require comp with `comp--compilable' set to nil to break
-    ;; circularity.
-    (let ((comp--compilable nil))
-      (require 'comp))
-    (native--compile-async comp--delayed-sources nil 'late)
-    (setq comp--delayed-sources nil)))
-
-(declare-function native--compile-async "comp.el"
-                  (files &optional recursively load selector))
-(defun startup--honor-delayed-native-compilations ()
-  "Honor pending delayed deferred native compilations."
-  (when (and (native-comp-available-p)
-             comp--delayed-sources)
-    (startup--require-comp-safely))
-  (setq comp--compilable t))
-
 (defvar native-comp-eln-load-path)
 (defvar native-comp-jit-compilation)
 (defvar native-comp-enable-subr-trampolines)
@@ -846,8 +825,7 @@ It is the default value of the variable `top-level'."
                                 nil)))
             (setq env (cdr env)))))
       (when display
-        (setq process-environment (delete display process-environment)))))
-  (startup--honor-delayed-native-compilations))
+        (setq process-environment (delete display process-environment))))))
 
 ;; Precompute the keyboard equivalents in the menu bar items.
 ;; Command-line options supported by tty's:

src/comp.c

@@ -5199,17 +5199,9 @@ maybe_defer_native_compilation (Lisp_Object function_name,
 
   Fputhash (function_name, definition, Vcomp_deferred_pending_h);
 
-  /* This is so deferred compilation is able to compile comp
-     dependencies breaking circularity.  */
-  if (comp__compilable)
-    {
-      /* Startup is done, comp is usable.  */
-      CALL0I (startup--require-comp-safely);
-      CALLN (Ffuncall, intern_c_string ("native--compile-async"),
-	     src, Qnil, Qlate);
-    }
-  else
-    Vcomp__delayed_sources = Fcons (src, Vcomp__delayed_sources);
+  pending_funcalls
+    = Fcons (list (Qnative__compile_async, src, Qnil, Qlate),
+             pending_funcalls);
 }
 
 
@@ -5674,13 +5666,6 @@ void
 syms_of_comp (void)
 {
 #ifdef HAVE_NATIVE_COMP
-  DEFVAR_LISP ("comp--delayed-sources", Vcomp__delayed_sources,
-    doc: /* List of sources to be native-compiled when startup is finished.
-For internal use.  */);
-  DEFVAR_BOOL ("comp--compilable", comp__compilable,
-    doc: /* Non-nil when comp.el can be native compiled.
-For internal use. */);
-  /* Compiler control customizes.  */
   DEFVAR_BOOL ("native-comp-jit-compilation", native_comp_jit_compilation,
     doc: /* If non-nil, compile loaded .elc files asynchronously.
 
@@ -5798,6 +5783,8 @@ natively-compiled one.  */);
         build_pure_c_string ("eln file inconsistent with current runtime "
 			     "configuration, please recompile"));
 
+  DEFSYM (Qnative__compile_async, "native--compile-async");
+
   defsubr (&Scomp__subr_signature);
   defsubr (&Scomp_el_to_eln_rel_filename);
   defsubr (&Scomp_el_to_eln_filename);