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`](c1ebf8ab92/src/sysconfigpatcher.py (L61)).
2. Remove `-isysroot`, which we already do for newer builds.

crates/uv-python/src/interpreter.rs

@@ -46,7 +46,7 @@ pub struct Interpreter {
     sys_executable: PathBuf,
     sys_path: Vec<PathBuf>,
     stdlib: PathBuf,
-    sysconfig_prefix: Option<PathBuf>,
+    standalone: bool,
     tags: OnceLock<Tags>,
     target: Option<Target>,
     prefix: Option<Prefix>,
@@ -80,7 +80,7 @@ impl Interpreter {
             sys_executable: info.sys_executable,
             sys_path: info.sys_path,
             stdlib: info.stdlib,
-            sysconfig_prefix: info.sysconfig_prefix,
+            standalone: info.standalone,
             tags: OnceLock::new(),
             target: None,
             prefix: None,
@@ -368,11 +368,6 @@ impl Interpreter {
         &self.stdlib
     }
 
-    /// Return the `prefix` path for this Python interpreter, as returned by `sysconfig.get_config_var("prefix")`.
-    pub fn sysconfig_prefix(&self) -> Option<&Path> {
-        self.sysconfig_prefix.as_deref()
-    }
-
     /// Return the `purelib` path for this Python interpreter, as returned by `sysconfig.get_paths()`.
     pub fn purelib(&self) -> &Path {
         &self.scheme.purelib
@@ -441,8 +436,7 @@ impl Interpreter {
     ///
     /// See: <https://github.com/indygreg/python-build-standalone/issues/382>
     pub fn is_standalone(&self) -> bool {
-        self.sysconfig_prefix()
-            .is_some_and(|prefix| prefix == Path::new("/install"))
+        self.standalone
     }
 
     /// Return the [`Layout`] environment used to install wheels into this interpreter.
@@ -626,7 +620,7 @@ struct InterpreterInfo {
     sys_executable: PathBuf,
     sys_path: Vec<PathBuf>,
     stdlib: PathBuf,
-    sysconfig_prefix: Option<PathBuf>,
+    standalone: bool,
     pointer_size: PointerSize,
     gil_disabled: bool,
 }
@@ -854,6 +848,7 @@ mod tests {
                 "arch": "x86_64"
             },
             "manylinux_compatible": false,
+            "standalone": false,
             "markers": {
                 "implementation_name": "cpython",
                 "implementation_version": "3.12.0",