Revert "Fix some compilation warnings in non nativecomp build (bug#43892)"

This reverts commit 6606ec8e31.

lisp/emacs-lisp/advice.el

@@ -2052,8 +2052,6 @@ in that CLASS."
 		 function class name)))
     (error "ad-remove-advice: `%s' is not advised" function)))
 
-(declare-function comp-subr-trampoline-install "comp")
-
 ;;;###autoload
 (defun ad-add-advice (function advice class position)
   "Add a piece of ADVICE to FUNCTION's list of advices in CLASS.

lisp/emacs-lisp/find-func.el

@@ -178,8 +178,6 @@ See the functions `find-function' and `find-variable'."
             (setq name rel))))
     (unless (equal name library) name)))
 
-(defvar comp-eln-to-el-h)
-
 (defun find-library-name (library)
   "Return the absolute file name of the Emacs Lisp source of LIBRARY.
 LIBRARY should be a string (the name of the library)."

lisp/emacs-lisp/nadvice.el

@@ -316,8 +316,6 @@ is also interactive.  There are 3 cases:
   `(advice--add-function ,where (gv-ref ,(advice--normalize-place place))
                          ,function ,props))
 
-(declare-function comp-subr-trampoline-install "comp")
-
 ;;;###autoload
 (defun advice--add-function (where ref function props)
   (when (and (featurep 'nativecomp)