On OS X, currently there are (atleast) two places where
GTK+ might be installed. The default for gtkD is the native
Quartz port. The other one is the X11 version, which runs
under the separate X11 environment of OS X. You can
uncomment the version=darwinX11 in the gtkD toplevel dsss.conf file
to build gtkD for X11.
Currently gtkDgl (which uses gtkglext) is only available under X11,
because gtkglext is not yet ported to the Quartz backend.
On OS X, currently there are (atleast) two places where GTK+ might be installed. The default for gtkD is the native Quartz port. The other one is the X11 version, which runs under the separate X11 environment of OS X. You can uncomment the version=darwinX11 in the gtkD toplevel dsss.conf file to build gtkD for X11. Currently gtkDgl (which uses gtkglext) is only available under X11, because gtkglext is not yet ported to the Quartz backend.