wipe rustlib/rust before linking

When using `symlink_dir`, it first removes the existing link with `remove_dir`.
However, if the path isn't a link and contains files, `remove_dir` fails
with "DirectoryNotEmpty", which causes the symbolic linking to fail as well.

We have this problem on "rustlib/rust" linking. This change fixes it by clearing the
path before using `symlink_dir`.

Signed-off-by: onur-ozkan <[email protected]>

Author: onur-ozkan

src/bootstrap/src/core/build_steps/compile.rs

@@ -11,6 +11,7 @@ use std::collections::HashSet;
 use std::env;
 use std::ffi::OsStr;
 use std::fs;
+use std::fs::remove_dir_all;
 use std::io::prelude::*;
 use std::io::BufReader;
 use std::path::{Path, PathBuf};
@@ -1625,6 +1626,9 @@ impl Step for Sysroot {
         let sysroot_lib_rustlib_src = sysroot.join("lib/rustlib/src");
         t!(fs::create_dir_all(&sysroot_lib_rustlib_src));
         let sysroot_lib_rustlib_src_rust = sysroot_lib_rustlib_src.join("rust");
+        // This path may already contain files, which can cause symbolic linking to fail.
+        // Make sure the path doesn't exist before linking it.
+        let _ = remove_dir_all(&sysroot_lib_rustlib_src_rust);
         if let Err(e) = symlink_dir(&builder.config, &builder.src, &sysroot_lib_rustlib_src_rust) {
             eprintln!(
                 "WARNING: creating symbolic link `{}` to `{}` failed with {}",
@@ -1643,6 +1647,9 @@ impl Step for Sysroot {
         let sysroot_lib_rustlib_rustcsrc = sysroot.join("lib/rustlib/rustc-src");
         t!(fs::create_dir_all(&sysroot_lib_rustlib_rustcsrc));
         let sysroot_lib_rustlib_rustcsrc_rust = sysroot_lib_rustlib_rustcsrc.join("rust");
+        // This path may already contain files, which can cause symbolic linking to fail.
+        // Make sure the path doesn't exist before linking it.
+        let _ = remove_dir_all(&sysroot_lib_rustlib_rustcsrc_rust);
         if let Err(e) =
             symlink_dir(&builder.config, &builder.src, &sysroot_lib_rustlib_rustcsrc_rust)
         {