replace POGL_WINDOW_TYPE config with env var

Graphics/TriD/POGL/OpenGL.pm

@@ -85,11 +85,12 @@ See the documentation for the OpenGL module.
 More details to follow as the refactored TriD module
 interface and build environment matures
 
-=head1 FUNCTIONS
+=head1 CONFIG
 
-=head2 TBD
+Defaults to using L<OpenGL::GLUT> - override by setting the environment
+variable C<POGL_WINDOW_TYPE> to C<x11> (the default is C<glut>).
 
-=cut
+=head1 FUNCTIONS
 
 =head2 TBD
 
@@ -164,7 +165,7 @@ sub new {
    }
 
    # Use GLUT windows and event handling as the TriD default
-   $window_type ||= $PDL::Config{POGL_WINDOW_TYPE};
+   $window_type ||= $ENV{POGL_WINDOW_TYPE} || 'glut';
    # $window_type ||= 'x11';       # use X11 default until glut code is ready
 
    my $self;

perldl.conf

@@ -54,9 +54,6 @@
 #                       define => '',
 #                     },
 
-#       POGL_WINDOW_TYPE => 'x11',      # use X11+GLX for windows
-        POGL_WINDOW_TYPE => 'glut',     # use GLUT for windows
-
 # Link flags for the GSL libs, e.g. '-L/usr/local/lib -lgsl -lm'
         GSL_LIBS => undef, # use gsl-config