No longer requires cmake or ninja.

[jonathanpallant]

Untested on hardware.

[jonathanpallant]

Now tested (and fixed) on hardware.

➜  demo-app git:(remove-cmake) git describe --long --all
heads/remove-cmake-0-g6c4db77
➜  demo-app git:(remove-cmake) cargo run --release
    Finished `release` profile [optimized + debuginfo] target(s) in 0.06s
     Running `probe-rs run --chip nRF52840_xxAA target/thumbv7em-none-eabi/release/demo-app`
      Erasing ✔ [00:00:00] [####################################] 16.00 KiB/16.00 KiB @ 34.29 KiB/s (eta 0s )
  Programming ✔ [00:00:00] [####################################] 16.00 KiB/16.00 KiB @ 46.53 KiB/s (eta 0s )    Finished in 0.828s
<lvl> Hello, this is version unknown!
└─ demo_app::__cortex_m_rt_main @ src/main.rs:151
<lvl> Entering ThreadX kernel...
└─ demo_app::__cortex_m_rt_main @ src/main.rs:186
<lvl> In tx_application_define()...
└─ demo_app::tx_application_define @ src/main.rs:26
<lvl> Stack allocated @ 0x20037444
└─ demo_app::tx_application_define @ src/main.rs:59
<lvl> Thread spawned (entry=12345678) @ 0x2003f440
└─ demo_app::tx_application_define @ src/main.rs:85
<lvl> Stack allocated @ 0x2003944c
└─ demo_app::tx_application_define @ src/main.rs:102
<lvl> Thread spawned (entry=aabbccdd) @ 0x2003f4f8
└─ demo_app::tx_application_define @ src/main.rs:128
<lvl> I am my_thread(12345678)
└─ demo_app::my_thread @ src/main.rs:136
<lvl> I am my_thread(aabbccdd)
└─ demo_app::my_thread @ src/main.rs:136
<lvl> I am my_thread(12345678), count = 1
└─ demo_app::my_thread @ src/main.rs:145
<lvl> I am my_thread(aabbccdd), count = 1
└─ demo_app::my_thread @ src/main.rs:145
<lvl> I am my_thread(12345678), count = 2
└─ demo_app::my_thread @ src/main.rs:145
<lvl> I am my_thread(aabbccdd), count = 2
└─ demo_app::my_thread @ src/main.rs:145

[miguelraz]

This builds locally after running git submodule update --init.
I'm approving and leaving it up to JP on where to leave that command for setting up.