Disable use of glversion for autodetection of GL features. This would require X
and I am not sure Xvfb would provide the same set of capabilities. Upstream also
includes a gl_exclude.h already that works for us, so just skip the detection.
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -798,192 +798,10 @@
 sub get_extensions
 {
   my($found,$no_excl) = @_;
-  print "Testing for OpenGL Extensions\n" if ($verbose);
-
-  # clean up previous output files
-  my $exc_file = 'gl_exclude.h';
-  unlink($exc_file) if (-e $exc_file);
-  my $glv_file = 'utils/glversion.txt';
-  unlink($glv_file) if (-e $glv_file);
-
-  # Only run the rest if GLUT is installed
-  print "Testing GLUT version\n" if ($verbose);
-  my($lib,$def);
-  if ($found->{FREEGLUT32} || $found->{FREEGLUT})
-  {
-    $lib = $found->{FREEGLUT32} || $found->{FREEGLUT};
-    $def = "HAVE_FREEGLUT";
-  }
-  elsif ($found->{GLUT32} || $found->{GLUT})
-  {
-    $lib = $found->{GLUT32} || $found->{GLUT};
-    $def = "HAVE_GLUT";
-  }
-  elsif ($verbose)
-  {
-    print "GLUT not found\n";
-  }
-
-  # Platform-specific makefiles for glversion
-  my $make_ver;
-  if ($IS_STRAWBERRY)
-  {
-    $make_ver = "&strawberry.bat";
-    print "strawberry glversion: '$make_ver'\n" if $verbose>1;
-  }
-  elsif ($IS_MINGW)
-  {
-    $make_ver = "&mingw.bat";
-    print "mingw glversion: '$make_ver'\n" if $verbose>1;
-  }
-  elsif ($IS_W32API)
-  {
-    $make_ver = ";make -f Makefile.cygwin " .  (length($lib) ? "GLUT_LIB=$lib " : "") . (length($def) ? "GLUT_DEF=$def " : "");
-    print "cygwin glversion: '$make_ver'\n" if $verbose>1;
-  }
-  elsif ($^O eq 'MSWin32')
-  {
-    $make_ver = '&nmake -f makefile.mak ' . (length($def) ? "GLUT_DEF=$def " : "");
-    print "MSWin32 glversion: '$make_ver'\n" if $verbose>1;
-  }
-  elsif ($^O eq 'darwin')
-  {
-    $make_ver = ";make -f Makefile.macosx " .  (length($lib) ? "GLUT_LIB=$lib " : "") . (length($def) ? "GLUT_DEF=$def " : "");
-    print "MacOSX glversion: '$make_ver'\n" if $verbose>1;
-  }
-  else
-  {
-    if ($ENV{TERM} ne 'xterm')
-    {
-      print "\nIn order to test your GPU's capabilities, run this make under an X11 shell\n\n";
-    }
-
-    $make_ver = ";make -f Makefile " .  (length($lib) ? "GLUT_LIB=$lib " : "") . (length($def) ? "GLUT_DEF=$def " : "");
-    print "glversion: '$make_ver'\n" if $verbose>1;
-  }
-  my $exec = 'cd utils'."$make_ver clean".$make_ver;
-  print "glversion: $exec\n" if ($verbose);
-  my $stat = `$exec`;
-  print "\n$stat\n\n" if ($verbose);
-  unlink "utils/freeglut.dll" or die "could not remove temporary freeglut: $!" if -f "utils/freeglut.dll";
-
-  # Parse glversion.txt file
-  open GLDATA, $glv_file or die "get_extensions: could not open $glv_file: $!\n";
-  my $gldata = {};
-  my @gldata = <GLDATA>;
-  close(GLDATA);
-
-  foreach my $line (@gldata)
-  {
-    $line =~ s|[\r\n]+||;
-    my($key,$val) = split('=',$line);
-    $gldata->{$key} = $val;
-  }
-  die "get_extensions: no extensions found in $glv_file\n" if !keys %$gldata;
-
-  print "This looks like OpenGL Version: $gldata->{VERSION}\n";
-
-  # Parse glext_procs.h file
-  open GLEXT, "glext_procs.h" or die "get_extensions: could not open glext_procs.h: $!\n";
-  my @lines = <GLEXT>;
-  close(GLEXT);
-
-  my $no_ext = {};
-  foreach my $line (@lines)
-  {
-    next if ($line !~ m|\#ifndef NO_([^\s]+)|);
-    my $ext = $1;
-    next if ($ext =~ m|^GL_VERSION_|);
-    $no_ext->{$ext}++;
-  }
-
-
-  # Create gl_exclude.h
-  die "Unable to write to $exc_file\n" if (!open(GLEXC,">$exc_file"));
-  print GLEXC "// OpenGL Extension Exclusions - may be modified before building.\n";
-  print GLEXC "//\n";
-  print GLEXC "// Generated for ".$gldata->{VENDOR}.", ".$gldata->{RENDERER}."\n";
-  print GLEXC "// OpenGL v".$gldata->{VERSION}.", using ";
-
-  # Fix GLUT flags based on results
-  if ($gldata->{FREEGLUT})
-  {
-    print 'Found FreeGLUT v'.$gldata->{FREEGLUT}."\n";
-    print GLEXC 'FreeGLUT v'.$gldata->{FREEGLUT}."\n";
-
-    if (!$found->{FREEGLUT} && !$found->{FREEGLUT32})
-    {
-      $found->{FREEGLUT} = $lib;
-    }
-  }
-  elsif ($gldata->{GLUT})
-  {
-    print "Found GLUT - Version: $gldata->{GLUT}\n";
-  }
-  else
-  {
-    print "Found no GLUT\n"
-  }
-
-  my $GL_VERSION;
-  my($GL_VERSION_MAJOR, $GL_VERSION_MINOR);
-  if ($gldata->{VERSION} =~ m|^(\d\.\d+)|)
-  {
-    $GL_VERSION = $1;
-    ($GL_VERSION_MAJOR,$GL_VERSION_MINOR) = split('.', $GL_VERSION);
-  }
-
-  # Make an empty exclusion file if a Windows distribution build
-  if ($no_excl)
-  {
-    print "OpenGL Extension exclusions disabled\n";
-    print GLEXC "//\n";
-    print GLEXC "// Exclusions omitted for distribution build.\n";
-  }
-  else
-  {
-    print GLEXC "\n";
-    if ($GL_VERSION)
-    {
-      print GLEXC "#define NO_GL_VERSION_4_5\n" if ($GL_VERSION < 4.5);
-      print GLEXC "#define NO_GL_VERSION_4_4\n" if ($GL_VERSION < 4.4);
-      print GLEXC "#define NO_GL_VERSION_4_3\n" if ($GL_VERSION < 4.3);
-      print GLEXC "#define NO_GL_VERSION_4_2\n" if ($GL_VERSION < 4.2);
-      print GLEXC "#define NO_GL_VERSION_4_1\n" if ($GL_VERSION < 4.1);
-      print GLEXC "#define NO_GL_VERSION_4_0\n" if ($GL_VERSION < 4.0);
-      print GLEXC "#define NO_GL_VERSION_3_3\n" if ($GL_VERSION < 3.3);
-      print GLEXC "#define NO_GL_VERSION_3_2\n" if ($GL_VERSION < 3.2);
-      print GLEXC "#define NO_GL_VERSION_3_1\n" if ($GL_VERSION < 3.1);
-      print GLEXC "#define NO_GL_VERSION_3_0\n" if ($GL_VERSION < 3.0);
-      print GLEXC "#define NO_GL_VERSION_2_1\n" if ($GL_VERSION < 2.1);
-      print GLEXC "#define NO_GL_VERSION_2_0\n" if ($GL_VERSION < 2.0);
-      print GLEXC "#define NO_GL_VERSION_1_5\n" if ($GL_VERSION < 1.5);
-      print GLEXC "#define NO_GL_VERSION_1_4\n" if ($GL_VERSION < 1.4);
-      print GLEXC "#define NO_GL_VERSION_1_3\n" if ($GL_VERSION < 1.3);
-      print GLEXC "#define NO_GL_VERSION_1_2\n" if ($GL_VERSION < 1.2);
-      print GLEXC "#define NO_GL_VERSION_1_1\n" if ($GL_VERSION < 1.1);
-    }
-
-    foreach my $ext (split(' ',$gldata->{EXTENSIONS}))
-    {
-      next if (!$no_ext->{$ext});
-      $no_ext->{$ext} = 0;
-    }
-
-    foreach my $ext (sort keys(%$no_ext))
-    {
-      next if (!$no_ext->{$ext});
-      print GLEXC "#define NO_$ext\n";
-    }
-  }
-
-  close(GLEXC);
-
 
   # return Distributable Defs
   print "Have Version Data\n" if ($verbose);
   my $defines = '-DHAVE_VER';
-  $defines .= " -DGL_VERSION_USED=$GL_VERSION" if ($GL_VERSION);
   return $defines;
 }