Fixes compilation on *BSD systems.

wineps.drv: Many MacOSX generated ppd files don't include a *ColorDevice line. Treat these as if they were colour.

secur32: SealMessage and UnsealMessage are aliases of EncryptMessage and DecryptMessage respectively.

(reported by Kai Blin).

winex11.drv: Spring cleanup in X11DRV_setup_opengl_visual, and added one new visual config (with aux buffers).

The hwstretch blit code creates a new texture each time it is called
to back up the back buffer and releases it afterwards. It is more
efficient to keep the texture and release it with the surface.