On Debian, the rustc-web package provides a newer Rust compiler (1.78)
for all architectures except mips64el.
On Ubuntu, Rust versions up to 1.80 (?) are available as of this writing
for both Jammy (22.04) and Noble (24.04). However, the path to rustc
and rustdoc must be provided by hand to the configure script using
either command line arguments or environment variables.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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