Try osascript before zenity and xmessage
Try osascript before zenity and xmessage

Prior to this commit, on macOS, when the xmessage command is available
(say due to xquartz package being installed), the end of timebox message
is displayed with xmessage instead of osascript.

This commit increases the precedence of osascript so that osascript is
tried before trying xmessage to ensure that the message looks like a
native alert on macOS.

susam/timeboxing