Rollup merge of rust-lang#93152 - ivmarkov:master, r=m-ou-se

Fix STD compilation for the ESP-IDF target (regression from CVE-2022-21658)

Commit rust-lang@54e22eb broke the compilation of STD for the ESP-IDF embedded "unix-like" Tier 3 target, because the fix for [CVE-2022-21658](https://blog.rust-lang.org/2022/01/20/Rust-1.58.1.html) uses [libc flags](https://github.com/esp-rs/esp-idf-svc/runs/4892221554?check_suite_focus=true) which are not supported on the ESP-IDF platform.

This PR simply redirects the ESP-IDF compilation to the "classic" implementation, similar to REDOX. This should be safe because:
* Neither of the two filesystems supported by ESP-IDF (spiffs and fatfs) support [symlinks](https://github.com/natevw/fatfs/blob/master/README.md) in the first place
* There is no notion of fs permissions at all, as the ESP-IDF is an embedded platform that does not have the notion of users, groups, etc.
* Similarly, ESP-IDF has just one "process" - the firmware itself - which contains the user code and the "OS" fused together and running with all permissions

Author: matthiaskrgr

library/std/src/sys/unix/fs.rs

@@ -1448,8 +1448,8 @@ pub fn chroot(dir: &Path) -> io::Result<()> {
 
 pub use remove_dir_impl::remove_dir_all;
 
-// Fallback for REDOX
-#[cfg(target_os = "redox")]
+// Fallback for REDOX and ESP-IDF
+#[cfg(any(target_os = "redox", target_os = "espidf"))]
 mod remove_dir_impl {
     pub use crate::sys_common::fs::remove_dir_all;
 }
@@ -1573,7 +1573,11 @@ mod remove_dir_impl {
 }
 
 // Modern implementation using openat(), unlinkat() and fdopendir()
-#[cfg(not(any(all(target_os = "macos", target_arch = "x86_64"), target_os = "redox")))]
+#[cfg(not(any(
+    all(target_os = "macos", target_arch = "x86_64"),
+    target_os = "redox",
+    target_os = "espidf"
+)))]
 mod remove_dir_impl {
     use super::{cstr, lstat, Dir, DirEntry, InnerReadDir, ReadDir};
     use crate::ffi::CStr;