Add a proper kernel interface `INotifications` for the notifications component instead of using a C style interface.
Add parameter for the application name when initializing notifications to avoid hardcoding the application name.
The implementation for macOS is kept in Objective-C and a TODO is added, as the API we are currently using appears to be deprecated.
- Haiku is Unix-like, but it still doesn't use libnotify.
- Haiku comes with its own sets of definitions for certain long variables.
There's still a problem revolving around the variables, but I removed a
duplicate, conflicting definition on the Haiku platform.
- Changed some definition-related logic in detect.h, because the gcc compiler
in Haiku (version 8.3.0) complained about duplicate definitions. I chose to
use 'unknown' rather than an empty string on one occasion.
- Changed size of m_aLastSoundPlayed[CHAT_NUM] in
`src/game/client/components/chat.cpp` due to an undocumented/undiscovered bug
in Haiku.
Add libnotify support for linux client
Also unify notification management
Make libnotify mandatory for the client. It is installed on 100% of Arch
Linux systems and on 70% of Debian systems. I'd guess the remaining
Debian systems are servers.
Detect dependent libraries of `libnotify` using `pkg-config`. Remove
library-specific code from the game module. Decrement refcount for
libnotify notification object before leaving the function.