Client::new() panics when JACK is not installed

[robbert-vdh]

I'd expect this to return an error if JACK is not available, but right now it just panics on an unwrap.

When creating a client, the library immediately calls jack_set_error_function:

rust-jack/src/client/client_impl.rs

Lines 49 to 54 in 6133ac4

	pub fn new(client_name: &str, options: ClientOptions) -> Result<(Self, ClientStatus), Error> {
	let _m = CREATE_OR_DESTROY_CLIENT_MUTEX.lock().unwrap();
	unsafe {
	jack_sys::jack_set_error_function(Some(error_handler));
	jack_sys::jack_set_info_function(Some(info_handler));
	}

And those functions call jack_sys::library().unwrap():

rust-jack/jack-sys/build.rs

Line 54 in 6133ac4

writeln!(out, " let library = crate::library().unwrap();").unwrap();

So if the library is not available or cannot be loaded, creating a client will panic instead of returning an error.

[Be-ing]

This is a regression from #172, which IMO should be reverted.

[Be-ing]

I think you can fix this by using version 0.9.2.

[robbert-vdh]

I fixed this with #177.