Build fail due to pkg-config or alsa

[jupart]

-------------------------
error: failed to run custom build command for `alsa-sys v0.1.1`
process didn't exit successfully: `<snipped path>/skirm/target/debug/build/alsa-sys-f0b05e88fa3b0ec9/build-script-build` (exit code: 101)
--- stderr
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: "Failed to run `\"pkg-config\" \"--libs\" \"--cflags\" \"alsa\"`: No such file or directory (os error 2)"', /checkout/src/libcore/result.rs:916:5
note: Run with `RUST_BACKTRACE=1` for a backtrace.
-------------------------

[jupart]

Should be fixed by using ggez 0.4 or newer, which makes use of rust-sdl2 0.31 or newer.