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, 5 insertions, 8 deletions

diff --git a/src/libstd/sys/vxworks/stack_overflow.rs b/src/libstd/sys/vxworks/stack_overflow.rs
index 08e7b310ca1..7b58c83193b 100644
--- a/src/libstd/sys/vxworks/stack_overflow.rs
+++ b/src/libstd/sys/vxworks/stack_overflow.rs
@@ -1,12 +1,12 @@
 #![cfg_attr(test, allow(dead_code))]
 
-use self::imp::{make_handler, drop_handler};
+use self::imp::{drop_handler, make_handler};
 
 pub use self::imp::cleanup;
 pub use self::imp::init;
 
 pub struct Handler {
-    _data: *mut libc::c_void
+    _data: *mut libc::c_void,
 }
 
 impl Handler {
@@ -26,16 +26,13 @@ impl Drop for Handler {
 mod imp {
     use crate::ptr;
 
-    pub unsafe fn init() {
-    }
+    pub unsafe fn init() {}
 
-    pub unsafe fn cleanup() {
-    }
+    pub unsafe fn cleanup() {}
 
     pub unsafe fn make_handler() -> super::Handler {
         super::Handler { _data: ptr::null_mut() }
     }
 
-    pub unsafe fn drop_handler(_handler: &mut super::Handler) {
-    }
+    pub unsafe fn drop_handler(_handler: &mut super::Handler) {}
 }