rev.22 fails when SDL 1.2 isnt present.

[LinoBigatti]

Configuring the rev.22 release errors out if sdl 1.2 isnt provided. This normally wouldnt be an issue, since you can just install sdl1.2, but Im trying to create a gentoo ebuild for the project and I need to use releases for this. I have 2 solutions in mind:

• Fixing the issue on the rev.22 tag
• Creating a new release with the new CMAKE system, under which this issue doesnt seem to occur.

Let me know what yall think.

[LinoBigatti]

This is apparently because it cant find the macro on the system when sdl isnt installed. Im not sure if a replacement which doesnt fail under these conditions exists