runtime: Broken build on Linux ARM64 host

Looks like there are at least two issues with building on Linux ARM64 hosts:

Incorrect System.Private.CoreLib.dll variant is built. According to the logs and the artifact directory the output is for “Linux.x64”. The CoreCLR native part is correctly built as “Linux.arm64”.
cmake detection seems inconsistent. Early in the build it executes cmake just fine but later on it complains about the version being too old. The machine has cmake 3.17 installed from source to /usr/local/bin/ and symlinked to /usr/bin/.

Full log attached: 10.txt

About this issue

Let’s close this once #34300 is merged.

It feels nice to get lucky and fix an issue while intending to fix another one 😄

I’ve linked this on my PR description to close it automatically once it’s merged.

It was incremental build from the last failure point, not a clean one, but it eventually finished:

Build succeeded.
    0 Warning(s)
    0 Error(s)

Time Elapsed 01:22:41.19

Let’s close this once #34300 is merged.