package/rustc: fix BR2_PACKAGE_HOST_RUSTC_ARCH for ARMv5
BR2_PACKAGE_HOST_RUSTC_ARCH only had a special value for
BR2_ARM_CPU_ARMV7A, but it also needs a special value for
BR2_ARM_CPU_ARMV5, as the pre-compiled Rust standard library for
ARMv5TE is identified with the "armv5te" architecture name, see
https://doc.rust-lang.org/nightly/rustc/platform-support.html.
We noticed this because Rust binaries wouldn't work on an ARMv5
platform (Illegal instruction). This was due to the usage of the
arm-unknown-linux-gnueabi variant of the Rust standard library, which
is for ARMv6. Thanks to this commit, we correctly use the
armv5te-unknown-linux-gnueabi variant, and Rust binaries work properly
on ARMv5TE.
A better approach would be to do the conversion from architecture
options to Rust tuples in a single string symbol that also defines the
supported architectures, similar to how it's done in e.g. openblas.
However, that's a much bigger change. So for now, just do the easy thing
and fix this one issue.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Thomas Petazzoni