opengl w/ threaded perl

gistfile1.txt

Bareword "GLUT_RGBA" not allowed while "strict subs" in use at tmp/req_opengl.pl line 10.
Bareword "GLUT_DOUBLE" not allowed while "strict subs" in use at tmp/req_opengl.pl line 10.
Bareword "GLUT_ALPHA" not allowed while "strict subs" in use at tmp/req_opengl.pl line 10.
Bareword "GLUT_DEPTH" not allowed while "strict subs" in use at tmp/req_opengl.pl line 10.

nothr.pl

use strict;
use warnings;
require OpenGL;
OpenGL->import(':all');

glutInit();
glutInitDisplayMode(GLUT_RGBA|GLUT_DOUBLE|GLUT_ALPHA|GLUT_DEPTH);

req_opengl.pl

use strict;
use warnings;
use threads;

threads->create(sub {
    require OpenGL;
    OpenGL->import(':all');
    glutInit();
    glutInitDisplayMode(GLUT_RGBA|GLUT_DOUBLE|GLUT_ALPHA|GLUT_DEPTH);
})->detach;

solution.pl

# adding () after constant names or
require OpenGL;
OpenGL->import(qw(:glfunctions :glconstants));
require subs;
subs->import(@{$OpenGL::EXPORT_TAGS{glconstants}}); 
# not worked