chromium: Depend on libstd-rs instead of rust

[MaxIhlenfeldt]

Fixes #792.

Build and patch changes:

In #782, we decided to depend on rust instead of libstd-rs, because the latter didn't include libprofiler_builtins and also used a naming scheme that trips up Chromium.

However, in #791 we decided to patch Chromium so that it doesn't need libprofiler_builtins any more, because the master version of the rust recipe also doesn't include it.

Finally, while investigating #792 it turned out that our approach breaks as soon as we have something that depends on libstd-rs in our dependency graph. In that scenario, both libstd-rs and rust (the latter due to our bbappend file) install Rust libraries to /usr/lib/rustlib. This first leads to Chromium build system errors (due to libstd-rs's naming scheme), and after fixing these to Rust compiler errors due to multiple versions being present.

The conclusion is now that we can depend on libstd-rs we should do so. This only requires a small change to Chromium's Rust build scripts to adapt them to the slightly different naming scheme.

License changes:

Added licenses: none.

Removed licenses: none.

Updated licenses: none.

Test-built:

• chromium-wayland:

• nanbield, clang, MACHINE=qemuarm64

• chromium-x11:

• master, clang, MACHINE=qemuarm