Android cross environment isn't fully delocalised

[freakboy3742]

Describe the bug

The xvenv environment created for Android contains definitions for CC and other build tools that reference the full path to ANDROID_HOME on the machine where Python was built.

Steps to reproduce

1. Create and activate an Android xvenv
2. Run `python -c "import sysconfig; print(sysconfig.get_config_var('CC'))"
3. See a path like /Users/msmith/Library/Android/sdk/ndk/27.2.12479018/toolchains/llvm/prebuilt/darwin-x86_64/bin/aarch64-linux-android21-clang, even if you're not msmith.

Expected behavior

Portions of the sysconfig file that include references to the build machine (especially ANDROID_HOME) should be delocalised.

Screenshots

No response

Environment

• Operating System: Any (but targing Android)
• Python version: 3.13.5
• Software versions:
  • xbuild: 0.2.0

Logs

Additional context

cibuildwheel avoids this by invoking android_env.sh to set variables in the Android environment. It may be appropriate for xbuild to do the same - although it's unclear where that environmental configuration would be applied.