Rollup merge of rust-lang#138765 - Berrysoft:cygwin-thread-name, r=joboet

Fix Thread::set_name on cygwin

Just like Linux, Cygwin also sets a limitation to thread name.

https://github.com/cygwin/cygwin/blob/8e50c7af7c49819245739d6f626f6fecc394ef7f/winsup/cygwin/thread.cc#L3175

Author: matthiaskrgr

library/std/src/sys/pal/unix/thread.rs

@@ -143,8 +143,8 @@ impl Thread {
     pub fn set_name(name: &CStr) {
         unsafe {
             cfg_if::cfg_if! {
-                if #[cfg(target_os = "linux")] {
-                    // Linux limits the allowed length of the name.
+                if #[cfg(any(target_os = "linux", target_os = "cygwin"))] {
+                    // Linux and Cygwin limits the allowed length of the name.
                     const TASK_COMM_LEN: usize = 16;
                     let name = truncate_cstr::<{ TASK_COMM_LEN }>(name);
                 } else {
@@ -346,6 +346,7 @@ impl Drop for Thread {
     target_os = "solaris",
     target_os = "illumos",
     target_os = "vxworks",
+    target_os = "cygwin",
     target_vendor = "apple",
 ))]
 fn truncate_cstr<const MAX_WITH_NUL: usize>(cstr: &CStr) -> [libc::c_char; MAX_WITH_NUL] {