fix fcntl binding on darwin

core/os/os_darwin.odin

@@ -440,7 +440,7 @@ foreign libc {
 	@(link_name="closedir")         _unix_closedir      :: proc(dirp: Dir) -> c.int ---
 	@(link_name="rewinddir")        _unix_rewinddir     :: proc(dirp: Dir) ---
 
-	@(link_name="__fcntl")          _unix__fcntl        :: proc(fd: Handle, cmd: c.int, #c_vararg args: ..any) -> c.int ---
+	@(link_name="__fcntl")          _unix__fcntl        :: proc(fd: Handle, cmd: c.int, arg: uintptr) -> c.int ---
 
 	@(link_name="rename") _unix_rename :: proc(old: cstring, new: cstring) -> c.int ---
 	@(link_name="remove") _unix_remove :: proc(path: cstring) -> c.int ---
@@ -794,14 +794,14 @@ _readlink :: proc(path: string) -> (string, Errno) {
 }
 
 absolute_path_from_handle :: proc(fd: Handle) -> (string, Errno) {
-	buf : [256]byte
-	res  := _unix__fcntl(fd, F_GETPATH, &buf[0])
-	if	res != 0 {
-		return "", Errno(get_last_error())
+	buf: [DARWIN_MAXPATHLEN]byte
+	_, err := fcntl(int(fd), F_GETPATH, int(uintptr(&buf[0])))
+	if err != ERROR_NONE {
+		return "", err
 	}
 
 	path := strings.clone_from_cstring(cstring(&buf[0]))
-	return path, ERROR_NONE
+	return path, err
 }
 
 absolute_path_from_relative :: proc(rel: string) -> (path: string, err: Errno) {
@@ -1068,7 +1068,7 @@ shutdown :: proc(sd: Socket, how: int) -> (Errno) {
 }
 
 fcntl :: proc(fd: int, cmd: int, arg: int) -> (int, Errno) {
-	result := _unix__fcntl(Handle(fd), c.int(cmd), c.int(arg))
+	result := _unix__fcntl(Handle(fd), c.int(cmd), uintptr(arg))
 	if result < 0 {
 		return 0, Errno(get_last_error())
 	}