Fixup readme

README.md

@@ -4,22 +4,24 @@
 
 ### Prerequisites
 
-- Recent linux machine of some kind required for development
-
-> [!NOTE]
-> I might be able to make this work on Mac if folks are interested and can help test.
-
+- Recent `x86_64` linux machine of some kind required for development
 - Bash (you very likely have this)
 - [Docker](https://www.docker.com/) (install through your package manager
 - Cargo / Rust (install via [`rustup`](https://rustup.rs/))
-- [just](https://github.com/casey/just) (install through your package manager or cargo)
 
-> [!WARNING]
-> System privileges required for testing!
-> This project requires root privileges to run the tests.
-> This is because the tests require access to raw network interfaces.
-> You can either run in docker or with `sudo`.
-> `sudo` happens by default when you run `cargo test`.
+  * :warning: You need a recent version of rust (1.82.0 or better) to build the project.
+
+    ```bash
+    rustup update
+    ```
+  * :warning: You need to install both the glibc and musl targets to use the default builds.
+
+    ```bash
+    rustup target add x86_64-unknown-linux-gnu
+    rustup target add x86_64-unknown-linux-musl
+    ```
+
+- [just](https://github.com/casey/just) (install through your package manager or cargo)
 
 ## Step 0. Clone the repository
 
@@ -64,27 +66,49 @@ just fake-nix
 At this point you should be able to run
 
 ```bash
-cargo build
+just cargo build
 ```
 
 You should now have statically linked ELF executables in `target/x86_64-unknown-linux-gnu/debug/scratch` and `target/x86_64-unknown-linux-musl/debug/scratch`.
 
-Additionally, you can run
+You can build in release mode with
 
 ```bash
-just build
+just cargo build --profile=release
 ```
 
-## Step 4. Run the tests
+at which point the executables will be in `target/x86_64-unknown-linux-gnu/release/scratch` and `target/x86_64-unknown-linux-musl/release/scratch`.
 
-To run the test suite under glibc
+## Step 4. Run the tests (debug mode)
+
+To run the test suite you can run 
 
 ```bash
-cargo test --target x86_64-unknown-linux-gnu
+just cargo test
 ```
 
-To run the test suite under musl
+By default, this will run both the musl and glibc tests.
+To run the test suite under glibc or musl specifically, try
 
 ```bash
-cargo test --target x86_64-unknown-linux-musl
+just cargo test --target x86_64-unknown-linux-gnu
 ```
+
+or
+
+```bash
+just cargo test --target x86_64-unknown-linux-musl
+```
+
+To run the test suite under release mode
+
+```bash
+just cargo test --profile=release
+```
+
+> [!NOTE]
+> Why the `just` in `just cargo build ...`?
+> 
+> `just` is computing the correct `RUSTFLAGS` for us depending on the profile.
+> After that it just calls `cargo build`.
+> Normally we would include those kinds of setting in `Cargo.toml` but `cargo` can not currently express all the `RUSTFLAGS` we are using (thus the `just` wrapper).