Add better support for cross builds.

[Rot127]

Your checklist for this pull request

• I've documented or updated the documentation of every API function and struct this PR changes.
• I've added tests that prove my fix is effective or that my feature works (if possible)

Detailed description

Enhances the support for cross compilation.

TODO

• Allow to build without existing libyaml library (build it from source if required).
• Make cstest work for systems without libyaml
• Add build/test for s390x to CI.
• Add build/test for mips to CI.
• Add build/test for ppc to CI.
• Add build for Android to CI
• Add test for x64 disassembler big endian bug #2339

Test plan

Tests added.

Closing issues

closes #2531
closes #2771
closes #1518

[Rot127]

@Antelox Do you think we could also build Python packages for those more niche architectures like s390x?