This patch provides the ELPA version (for Emacs < 24.4) of nadvice.el's
advice-add the ability to handle anonymous advices.

I have tested with a simple example:


```emacs-lisp

(let* ((sym (make-symbol "nadvice λ")))
  (defalias sym (lambda (&rest args) '(1)))
  (advice-add sym :around (lambda (func &rest args)
                            (append (apply func args) '(2))))
  (vector
   ;; advised returned value
   (funcall sym)
   (progn
     (advice-remove sym (lambda (func &rest args)
                          (append (apply func args) '(2))))
     ;; unadvised returned value
     (funcall sym))))

;; => [(1 2) (1)]

```


In GNU Emacs 24.3.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.22.30)
 of 2020-04-04 on x86-01.bsys.centos.org
Windowing system distributor `The X.Org Foundation', version
 11.0.12201005
 
Configured using:
 `configure '--build=x86_64-redhat-linux-gnu'
 '--host=x86_64-redhat-linux-gnu' '--program-prefix='
 '--disable-dependency-tracking' '--prefix=/usr' '--exec-prefix=/usr'
 '--bindir=/usr/bin' '--sbindir=/usr/sbin' '--sysconfdir=/etc'
 '--datadir=/usr/share' '--includedir=/usr/include'
 '--libdir=/usr/lib64' '--libexecdir=/usr/libexec'
 '--localstatedir=/var' '--sharedstatedir=/var/lib'
 '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--with-dbus'
 '--with-gif' '--with-jpeg' '--with-png' '--with-rsvg' '--with-tiff'
 '--with-xft' '--with-xpm' '--with-x-toolkit=gtk3' '--with-gpm=no'
 'build_alias=x86_64-redhat-linux-gnu'
 'host_alias=x86_64-redhat-linux-gnu' 'CFLAGS=-DMAIL_USE_LOCKF -O2 -g
 -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
 -fstack-protector-strong --param=ssp-buffer-size=4
 -grecord-gcc-switches -m64 -mtune=generic' 'LDFLAGS=-Wl,-z,relro ''


-- 
Daanturo.