Try to somehow implement clock_res_get on Windows. (#124)

* Implement clock_time_get on Windows.

Also update misc_testsuite to include latest clock_time_get test
changes.

* Try to somehow implement clock_res_get on Windows.

* Fix 55ms

* Cache the perf counter resolution

* Fix integration tests

winx/src/lib.rs

@@ -25,6 +25,7 @@
 extern crate bitflags;
 
 pub mod file;
+pub mod time;
 pub mod winerror;
 
 use winerror::WinError;

winx/src/time.rs

@@ -0,0 +1,10 @@
+use cvt::cvt;
+use winapi::um::{profileapi::QueryPerformanceFrequency, winnt::LARGE_INTEGER};
+
+pub fn perf_counter_frequency() -> std::io::Result<u64> {
+    unsafe {
+        let mut frequency: LARGE_INTEGER = std::mem::zeroed();
+        cvt(QueryPerformanceFrequency(&mut frequency))?;
+        Ok(*frequency.QuadPart() as u64)
+    }
+}