sys/unix: add sysctlbyname for darwin

core/time/tsc_darwin.odin

@@ -1,21 +1,10 @@
 //+private
-//+build darwin
 package time
 
-import "core:c"
+import "core:sys/unix"
 
-foreign import libc "system:System.framework"
-foreign libc {
-	@(link_name="sysctlbyname") _sysctlbyname    :: proc(path: cstring, oldp: rawptr, oldlenp: rawptr, newp: rawptr, newlen: int) -> c.int ---
-}
-
-_get_tsc_frequency :: proc "contextless" () -> (u64, bool) {
-	tmp_freq : u64 = 0
-	tmp_size : i64 = size_of(tmp_freq)
-	ret := _sysctlbyname("machdep.tsc.frequency", &tmp_freq, &tmp_size, nil, 0)
-	if ret < 0 {
-		return 0, false
-	}
-
-	return tmp_freq, true
+_get_tsc_frequency :: proc "contextless" () -> (freq: u64, ok: bool) {
+	unix.sysctlbyname("machdep.tsc.frequency", &freq) or_return
+	ok = true
+	return
 }