_color_pack: define variable before using

include/colors.php

@@ -216,6 +216,7 @@ function _color_unpack($hex, $normalize = false) {
 
 ### Convert an RGB triplet to a hex color.
 function _color_pack($rgb, $normalize = false) {
+	$out = 0;
   foreach ($rgb as $k => $v) {
     $out |= (($v * ($normalize ? 255 : 1)) << (16 - $k * 8));
   }return '#'. str_pad(dechex($out), 6, 0, STR_PAD_LEFT);