Patch sysconfig data at install time (#9857)

## Summary

This PR reimplements
[`sysconfigpatcher`](https://github.com/bluss/sysconfigpatcher) in Rust
and applies it to our Python installations at install-time, ensuring
that the `sysconfig` data is more likely to be correct.

For now, we only rewrite prefixes (i.e., any path that starts with
`/install` gets rewritten to the correct absolute path for the current
machine).

Unlike `sysconfigpatcher`, this PR does not yet do any of the following:

- Patch `pkginfo` files.
- Change `clang` references to `cc`.

A few things that we should do as follow-ups, in my opinion:

1. Rewrite
[`AR`](https://github.com/bluss/sysconfigpatcher/blob/c1ebf8ab9274dcde255484d93ce0f1fd1f76a248/src/sysconfigpatcher.py#L61).
2. Remove `-isysroot`, which we already do for newer builds.

crates/uv-python/python/get_interpreter_info.py

@@ -573,7 +573,10 @@ def main() -> None:
         "sys_executable": sys.executable,
         "sys_path": sys.path,
         "stdlib": sysconfig.get_path("stdlib"),
-        "sysconfig_prefix": sysconfig.get_config_var("prefix"),
+        # Prior to the introduction of `sysconfig` patching, python-build-standalone installations would always use
+        # "/install" as the prefix. With `sysconfig` patching, we rewrite the prefix to match the actual installation
+        # location. So in newer versions, we also write a dedicated flag to indicate standalone builds.
+        "standalone": sysconfig.get_config_var("prefix") == "/install" or bool(sysconfig.get_config_var("PYTHON_BUILD_STANDALONE")),
         "scheme": get_scheme(),
         "virtualenv": get_virtualenv(),
         "platform": os_and_arch,