Starting with Ubuntu 17.10 the interface will be provided by an
extension (shipped by default):
https://github.com/ubuntu/gnome-shell-extension-appindicator
Legacy tray icons have been completely removed in GNOME 3.26. By
checking the interface, this will allow users of other distributions
with GNOME to also use Telegram's indicator with the extension.
Signed-off-by: Jan Niklas Hasse <jhasse@bixense.com> (github: jhasse)
Currently the build without implicitly included precompiled header
is not supported anyway (because Qt MOC source files do not include
stdafx.h, they include plain headers).
So when we decide to support building without implicitly included
precompiled headers we'll have to fix all the headers anyway.