bug#18384: 24.3.93; posn-col-row and posn-actual-col-row return different row number for point-min when header-line-format is non-nil

[Dmitry]

(Not a regression, same in Emacs 24.3 release, and apparently earlier versions).

1. Open a simple buffer; maybe an empty one.
2. (setq header-line-format "aaaa")
3. (posn-actual-col-row (posn-at-point (point-min)))
=> (0 . 1)
4. (posn-col-row (posn-at-point (point-min)))
=> (0 . -1)

I would also understand if the latter returned (0 . 0) instead of the
same value, but -1 seems obviously wrong.

http://debbugs.gnu.org/cgi/bugreport.cgi?bug=7390#40 ?

In GNU Emacs 24.3.93.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
 of 2014-08-18 on axl
Repository revision: 117447 eliz@gnu.org-20140817144850-xgexz1n2z8s4aiur
Windowing system distributor `The X.Org Foundation', version 11.0.11501000
System Description:     Ubuntu 14.04.1 LTS