bug#25204: 25.1.50; I can't change the scroll-lock setting when Emacs has the focus

[Dani Moncayo]

> FWIW: IMO, the default behavior should be let the scroll-lock key
> toggle the scroll-lock status.  Definitely.

For the record: I've just noticed the following inconsistency:

The same Emacs (-Q) binary[1] have different behaviors on different
MS-Windows variants.  With w32-scroll-modifier set to nil:
* On Windows 7 and 10,  the scroll-lock key does _not_ toggle the setting.
* On Windows 2003 server,  the scroll-lock key _does_ toggle the setting.

-- 
Dani Moncayo

[1] Build from the emacs-25 branch on 2016-11-12.