Actually dglOpenGL is okay, you just need to add "Classes" into the unit clauses (line #174).
The serious problems are in the Texture.pas:
- Remove "Windows" from the unit clause ... line #30
- Add "LCLType" into the unit clause ... line #30
- "CreateFile" is unknown on my Lazarus Linux ... line #146
- "ReadFile" is unknown on my Lazarus Linux ... line #153
- "MessageBox" is unknown on my Lazarus Linux ... line #148
- "CloseHandle" is unknown on my Lazarus Linux ... line #178
- "FileExists" is unknown on my Lazarus Linux ... line #329
- "Uppercase" is unknown on my Lazarus Linux ... line #518
...
Now you can see, too much issues. If only 3 or 4, I am sure I can fix it manually. My guess, the unknown issues is related with Windows unit.