package/rust: set musl-root for musl toolchains
Without musl-root in config.toml the build stop with the following error:
thread 'main' panicked at 'couldn't find libc.a in musl libdir: output/host/arm-buildroot-linux-musleabihf/sysroot/lib/lib', src/bootstrap/sanity.rs:192:25
musl-root is needed to provide the path to libc.a and libunwind.a because
rust link them statically into the standard library and liblibc [1].
For other libc, musl-root is not used and ignored [2].
[1] https://github.com/rust-lang/rust/commit/cd980b3bee5bd48e8a6cd4c0d7c8e0fb0fdb64dd
[2] https://github.com/rust-lang/rust/blob/1.58.1/src/bootstrap/sanity.rs#L181
Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
(cherry picked from commit a41b0f31dea3e62b006ac815bf628600676b328f)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Romain Naour