We have stumbled on an odd bug trying to install a package with
package-install-file in Emacs trunk. With Emacs 24.3.1 it works, with Emacs
trunk we get an error that a builtin library (thingatpt in this case) is
not available (for more details see the bottom of
https://github.com/quelpa/quelpa/issues/11).

The culprit seems to be this:

(package-built-in-p 'thingatpt '(0 0 0)) ; emacs 24.4
nil

(package-built-in-p 'thingatpt '(0 0 0)) ; emacs 24.3
t

but:

(package-built-in-p 'thingatpt) ; emacs 24.4
(thingatpt . [nil nil "get the `thing' at point"])

(package-built-in-p 'thingatpt) ; emacs 24.3
t

If you check list-packages you will also not find thingatpt in the list of
builtins in 24.4 which cannot be correct, right? Only packages that have a
version are listed which is the minority.

cheers,
steckerhalter