Remove unused cross compilation logic

[bastelfreak]

Short description

Checklist

I have:

• read the CONTRIBUTING.md document
• read and accepted the Developer Certificate of Origin document and added a Signed-off-by annotation to each of my commits
• read and accepted the AI Policy document and added Generated-by or Assisted-by annotations to each of my commits created with the help of an AI agent
• tested this code
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• added or modified regression test(s)
• added or modified unit test(s)

[ekohl]

How much of https://github.com/OpenVoxProject/puppet-runtime/blob/main/notes/cross-compiling.md is still relevant?

[bastelfreak]

FYI I pulled the powerpc removal into a dedicated PR: #180

[nmburgan]

How much of https://github.com/OpenVoxProject/puppet-runtime/blob/main/notes/cross-compiling.md is still relevant?

Some of it is relevant if we ever have to go the cross compilation route again (I really only forsee us doing that for MacOS x86_64 if we really have to after they remove Rosetta), but we aren't currently doing it at all.

[ekohl]

How many of the mentions of /opt/pl-build-tools are still relevant after we drop cross compiling?

[nmburgan]

Definitely all instances of pl-build-tools references we can remove

[bastelfreak]

A full compilation for also windows and macos: https://github.com/OpenVoxProject/puppet-runtime/actions/runs/25935830927