[GRASSLIST:5816] focus follows mouse on MacOSX

I found a neat little utility for MacOSX's X11 which came with one of
the Mac versions of the GIMP. It makes the window focus work like on a
regular UNIX setup, ie whatever window is under the mouse gets the
focus.

Adding an extra click everytime you switch between d.m & the graphics
monitor drives me nuts.

Comes with the gimp.app 2.2.3 installer:
  http://gimp-app.sourceforge.net/

[Turn On X11 Focus Follows Mouse.app]

I don't see a license with it; if it's Free software maybe we can
include it with Lorenzo's GRASS binaries for those that want it.

gimp-app contacts:
  http://sourceforge.net/projects/gimp-app/
  http://sourceforge.net/project/memberlist.php?group_id=104774

Hamish