Heavily improve time handling on Windows for time.now() and os.File_Info

core/sys/windows/kernel32.odin

@@ -249,6 +249,16 @@ foreign kernel32 {
 	GetModuleHandleA :: proc(lpModuleName: LPCSTR) -> HMODULE ---
 	GetSystemTimeAsFileTime :: proc(lpSystemTimeAsFileTime: LPFILETIME) ---
 	GetSystemTimePreciseAsFileTime :: proc(lpSystemTimeAsFileTime: LPFILETIME) ---
+	FileTimeToSystemTime :: proc(lpFileTime: ^FILETIME, lpSystemTime: ^SYSTEMTIME) -> BOOL ---
+	SystemTimeToTzSpecificLocalTime :: proc(
+		lpTimeZoneInformation: ^TIME_ZONE_INFORMATION,
+		lpUniversalTime: ^SYSTEMTIME,
+		lpLocalTime: ^SYSTEMTIME,
+	) -> BOOL ---
+	SystemTimeToFileTime :: proc(
+		lpSystemTime: ^SYSTEMTIME,
+		lpFileTime: LPFILETIME,
+	) -> BOOL ---
 	CreateEventW :: proc(
 		lpEventAttributes: LPSECURITY_ATTRIBUTES,
 		bManualReset: BOOL,

core/sys/windows/types.odin

@@ -2267,9 +2267,10 @@ FILETIME :: struct {
 
 FILETIME_as_unix_nanoseconds :: proc "contextless" (ft: FILETIME) -> i64 {
 	t := i64(u64(ft.dwLowDateTime) | u64(ft.dwHighDateTime) << 32)
-	return (t - 0x019db1ded53e8000) * 100
+	return (t - 116444736000000000) * 100
 }
 
+
 OVERLAPPED :: struct {
 	Internal: ^c_ulong,
 	InternalHigh: ^c_ulong,
@@ -2943,6 +2944,16 @@ SYSTEMTIME :: struct {
 	milliseconds: WORD,
 }
 
+TIME_ZONE_INFORMATION :: struct {
+	Bias:         LONG,
+	StandardName: [32]WCHAR,
+	StandardDate: SYSTEMTIME,
+	StandardBias: LONG,
+	DaylightName: [32]WCHAR,
+	DaylightDate: SYSTEMTIME,
+	DaylightBias: LONG,
+}
+
 
 @(private="file")
 IMAGE_DOS_HEADER :: struct {