Remove (outdated) comment about --with-opengl=windows being untested

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@32119 15284696-431f-4ddb-bdfa-cd5b030d7da7

configure.in

@@ -1133,8 +1133,6 @@ fi # $OPENGL_AQUA
 
 if test "$OPENGL_WINDOWS" = 1 ; then
 
-AC_MSG_WARN([*** --with-opengl=windows is untested.])
-
 # With OpenGL includes directory
 
 LOC_CHECK_INC_PATH(opengl,OpenGL,OPENGLINC)