bug#12577: 24.1; regression in with-timeout in emacs24

[Vivek Dasmohapatra <vivek@etla.org>]

The behaviour of with-timeout appears to have changed radically:

(with-timeout (5 "BLERG") (ignore "things") (message "HELLO"))

In emacs23:

The message form is executed and the return value is that of the 
message invocation ("HELLO").

In emacs24:

All forms after the first form in the BODY are ignored. They 
are not executed at all (not just a case of prog1 vs progn behaviour).
The return value is that of the first form in the body (ie the only
one that gets executed).

This is at odds with the documentation, which does not indicate
that any such change has occurred.

In addition, I am told that the interpretation of the 

   (SECONDS TIMEOUT-FORMS) 

part of the forms arguments has changed: 
It now appears to be interpreted as:

  (sec1 time1 ) (sec2 time2) … 

Instead.

I have confirmed the first difference in behaviour with several people
in #emacs on freenode, so it does not appear to be specific to my 
site.
----------------------------------------------------------------------------

In GNU Emacs 24.1.1 (x86_64-pc-linux-gnu, GTK+ Version 2.24.10)
 of 2012-08-23 on noise, modified by Debian
Windowing system distributor `The X.Org Foundation', version
 11.0.11203000
Configured using:
 `configure '--build' 'x86_64-linux-gnu' '--build' 'x86_64-linux-gnu'
 '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib'
 '--localstatedir=/var/lib' '--infodir=/usr/share/info'
 '--mandir=/usr/share/man' '--with-pop=yes'
 '--enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.1/site-lisp:/usr/share/emacs/site-lisp'
 '--with-crt-dir=/usr/lib/x86_64-linux-gnu' '--with-x=yes'
 '--with-x-toolkit=gtk' '--with-toolkit-scroll-bars'
 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -fstack-protector
 --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wall'
 'CPPFLAGS=-D_FORTIFY_SOURCE=2''