Fix issues with stat struct.

The stat struct was the format for the 64 bit version of stat. So we need to call stat64 to get the proper data.
Also we need to use _File_Time instead of File_Time because it is a compound value. 

These changes were tested and work on my computer, MacOS 64 bit.

core/os/os_darwin.odin

@@ -202,10 +202,10 @@ Stat :: struct {
 	gid:           u32, // Group ID of the file's group
 	rdev:          i32, // Device ID, if device
 
-	last_access:   File_Time, // Time of last access
-	modified:      File_Time, // Time of last modification
-	status_change: File_Time, // Time of last status change
-	created:       File_Time, // Time of creation
+	last_access:   _File_Time, // Time of last access
+	modified:      _File_Time, // Time of last modification
+	status_change: _File_Time, // Time of last status change
+	created:       _File_Time, // Time of creation
 
 	size:          i64,  // Size of the file, in bytes
 	blocks:        i64,  // Number of blocks allocated for the file
@@ -273,7 +273,7 @@ foreign libc {
 	@(link_name="lseek")   _unix_lseek   :: proc(fs: Handle, offset: int, whence: int) -> int ---;
 	@(link_name="gettid")  _unix_gettid  :: proc() -> u64 ---;
 	@(link_name="getpagesize") _unix_getpagesize :: proc() -> i32 ---;
-	@(link_name="stat")    _unix_stat    :: proc(path: cstring, stat: ^Stat) -> int ---;
+	@(link_name="stat64")    _unix_stat    :: proc(path: cstring, stat: ^Stat) -> int ---;
 	@(link_name="access")  _unix_access  :: proc(path: cstring, mask: int) -> int ---;
 
 	@(link_name="malloc")  _unix_malloc  :: proc(size: int) -> rawptr ---;