docs: explicitly mention need for musl
Most packages induce fairly obvious error messages when they're
missing, but musl-tools gives an obscure error that's not obviously
related.
@@ -86,6 +86,14 @@ The key prerequisites for the project are:
`rustup target add wasm32-unknown-unknown`
- Install additional tools (e.g. `rustfmt` and `clippy`) as indicated by the
[`Dockerfile`](/Dockerfile) contents.
+- **Support for [musl](https://musl.libc.org/)** (on Linux): The
+ [Oak Runtime](/docs/concepts.md#oak-runtime) is built as a
+ [fully static binary](https://doc.rust-lang.org/edition-guide/rust-2018/platform-and-target-support/musl-support-for-fully-static-binaries.html),
+ on Linux, which requires:
+ - the Rust `x86_64-unknown-linux-musl` target
+ (`rustup target add x86_64-unknown-linux-musl`)
+ - the [musl-tools](https://packages.debian.org/search?keywords=musl-tools)
+ package to be installed.
- **Bazel**: The [Bazel build system](https://bazel.build) is used for building
C++ code and managing its dependencies. These dependencies are listed in the
top-level [`WORKSPACE`](/WORKSPACE) file; see the
