Wrap rustc commands with sccache when building native build scripts.
More interesting will be using sscache for compiling for the target
architecture, but sccache currently refuses to cache with --sysroot.
This can be optimized further later on, get some initial support for
sccache in here first.
While at it, tweak the -vV logic to also support -V, start using semver
with this and add myself as maintainer of the package.
[ci:skip-build]: already built successfully in CI
d9830c6304