X.H.ServerMode: Only read the first ClientMessage data item
X.H.ServerMode: Only read the first ClientMessage data item

Atoms are at most 32-bit even on 64-bit platforms, per the X protocol,
despite them being stored in a CLong. Even if they weren't (and they
are, see /usr/include/X11/Xproto.h and
https://stackoverflow.com/a/23265984/3407728), xmonadctl isn't unpacking
the CLong into multiple data items.

xmonad/xmonad-contrib,xmonad/xmonad-contrib