Clean up core:time to be consistent across all platforms

core/time/time_windows.odin

@@ -1,22 +1,21 @@
+//+private
 package time
 
 import win32 "core:sys/windows"
 
-IS_SUPPORTED :: true
+_IS_SUPPORTED :: true
 
-now :: proc() -> Time {
+_now :: proc "contextless" () -> Time {
 	file_time: win32.FILETIME
 	win32.GetSystemTimeAsFileTime(&file_time)
 	ns := win32.FILETIME_as_unix_nanoseconds(file_time)
 	return Time{_nsec=ns}
 }
 
-sleep :: proc(d: Duration) {
+_sleep :: proc "contextless" (d: Duration) {
 	win32.Sleep(win32.DWORD(d/Millisecond))
 }
 
-
-
 _tick_now :: proc "contextless" () -> Tick {
 	mul_div_u64 :: proc "contextless" (val, num, den: i64) -> i64 {
 		q := val / den