When trying to play a sound, kitty prints an error message because it cannot find `libcanberra.so`:
```
Failed to load libcanberra.so, cannot play beep sound, with error: libcanberra.so.0.2.5: cannot open shared object file: No such file or directory
```
This is fixed by patching the path to the library.
The previous substitutution only worked by accident as make requires
environment variables to be enclosed in curly brackets as shown in this
excerpt from the build output:
> PYTHONPATH=YTHONPATH:.. HOME=MPDIR/nowhere sphinx-build -M html "." "_build" -T
The substituition is moved to the existing patch file to simplify the
builder expression.
Startup notification doesn't work in recent versions of Kitty:
> Traceback (most recent call last):
> File "/nix/store/3a3b0xd952gp8jw70k5kh3a4zhgzf0p7-kitty-0.12.3/bin/../lib/kitty/kitty/utils.py", line 216, in init_startup_notification
> return init_startup_notification_x11(window_handle, startup_id)
> File "/nix/store/3a3b0xd952gp8jw70k5kh3a4zhgzf0p7-kitty-0.12.3/bin/../lib/kitty/kitty/utils.py", line 201, in init_startup_notification_x11
> return init_x11_startup_notification(display, window_handle, sid)
> OSError: Failed to load libstartup-notification-1.so with error: libstartup-notification-1.so: cannot open shared object file: No such file or directory
Apparently dispatching of startup notification has been moved to a C
binding in kitty 0.6.0 [1] so the substituion had to be modified to reflect
that. Without this fix Kitty still works except that window managers
which depend on startup notifications to be fired (e.g. Awesome)
cannot apply special placement rules.
The substitution mechanism is also changed to use a patch file to detect
this kind of mistakes in the future.
[1]: b08f4ab593
