Use C-style struct for glDirectDrawClipper.

git-svn-id: https://www.williamfeely.info/svn/dxgl@447 8a90861a-4eca-46d5-b744-240ff16d0c4d
Missed a commit for header file.

git-svn-id: https://www.williamfeely.info/svn/dxgl@448 8a90861a-4eca-46d5-b744-240ff16d0c4d