Format libstd/sys with rustfmt

This commit applies rustfmt with rust-lang/rust's default settings to
files in src/libstd/sys *that are not involved in any currently open PR*
to minimize merge conflicts. THe list of files involved in open PRs was
determined by querying GitHub's GraphQL API with this script:
https://gist.github.com/dtolnay/aa9c34993dc051a4f344d1b10e4487e8

With the list of files from the script in outstanding_files, the
relevant commands were:

    $ find src/libstd/sys -name '*.rs' \
        | xargs rustfmt --edition=2018 --unstable-features --skip-children
    $ rg libstd/sys outstanding_files | xargs git checkout --

Repeating this process several months apart should get us coverage of
most of the rest of the files.

To confirm no funny business:

    $ git checkout $THIS_COMMIT^
    $ git show --pretty= --name-only $THIS_COMMIT \
        | xargs rustfmt --edition=2018 --unstable-features --skip-children
    $ git diff $THIS_COMMIT  # there should be no difference

1 files changed, 10 insertions, 15 deletions

diff --git a/src/libstd/sys/windows/thread_local.rs b/src/libstd/sys/windows/thread_local.rs
index 728257cdd4b..e0bb102b3af 100644
--- a/src/libstd/sys/windows/thread_local.rs
+++ b/src/libstd/sys/windows/thread_local.rs
@@ -5,7 +5,7 @@ use crate::sync::atomic::Ordering::SeqCst;
 use crate::sys::c;
 
 pub type Key = c::DWORD;
-pub type Dtor = unsafe extern fn(*mut u8);
+pub type Dtor = unsafe extern "C" fn(*mut u8);
 
 // Turns out, like pretty much everything, Windows is pretty close the
 // functionality that Unix provides, but slightly different! In the case of
@@ -111,11 +111,7 @@ struct Node {
 }
 
 unsafe fn register_dtor(key: Key, dtor: Dtor) {
-    let mut node = Box::new(Node {
-        key,
-        dtor,
-        next: ptr::null_mut(),
-    });
+    let mut node = Box::new(Node { key, dtor, next: ptr::null_mut() });
 
     let mut head = DTORS.load(SeqCst);
     loop {
@@ -192,15 +188,12 @@ unsafe fn register_dtor(key: Key, dtor: Dtor) {
 #[link_section = ".CRT$XLB"]
 #[allow(dead_code, unused_variables)]
 #[used] // we don't want LLVM eliminating this symbol for any reason, and
-        // when the symbol makes it to the linker the linker will take over
-pub static p_thread_callback: unsafe extern "system" fn(c::LPVOID, c::DWORD,
-                                                        c::LPVOID) =
-        on_tls_callback;
+// when the symbol makes it to the linker the linker will take over
+pub static p_thread_callback: unsafe extern "system" fn(c::LPVOID, c::DWORD, c::LPVOID) =
+    on_tls_callback;
 
 #[allow(dead_code, unused_variables)]
-unsafe extern "system" fn on_tls_callback(h: c::LPVOID,
-                                          dwReason: c::DWORD,
-                                          pv: c::LPVOID) {
+unsafe extern "system" fn on_tls_callback(h: c::LPVOID, dwReason: c::DWORD, pv: c::LPVOID) {
     if dwReason == c::DLL_THREAD_DETACH || dwReason == c::DLL_PROCESS_DETACH {
         run_dtors();
     }
@@ -210,7 +203,9 @@ unsafe extern "system" fn on_tls_callback(h: c::LPVOID,
     reference_tls_used();
     #[cfg(target_env = "msvc")]
     unsafe fn reference_tls_used() {
-        extern { static _tls_used: u8; }
+        extern "C" {
+            static _tls_used: u8;
+        }
         crate::intrinsics::volatile_load(&_tls_used);
     }
     #[cfg(not(target_env = "msvc"))]
@@ -222,7 +217,7 @@ unsafe fn run_dtors() {
     let mut any_run = true;
     for _ in 0..5 {
         if !any_run {
-            break
+            break;
         }
         any_run = false;
         let mut cur = DTORS.load(SeqCst);