misc Clippy cleanup

* Fix race conditions in the tests.  Two tests were grabbing a mutex but
  immediately dropping it.  Thank you, Clippy.

* Remove vestigial Windows support.  Remove some code added to support
  Windows in 2015.  Nix is no longer intended to ever run on Windows.

* Various other minor Clippy lints.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/time.rs b/src/time.rs
index e6c3f8de..f7da654a 100644
--- a/src/time.rs
+++ b/src/time.rs
@@ -185,9 +185,9 @@ impl ClockId {
     pub const CLOCK_VIRTUAL: ClockId = ClockId(libc::CLOCK_VIRTUAL);
 }
 
-impl Into<clockid_t> for ClockId {
-    fn into(self) -> clockid_t {
-        self.as_raw()
+impl From<ClockId> for clockid_t {
+    fn from(clock_id: ClockId) -> Self {
+        clock_id.as_raw()
     }
 }