Description :: Normally a double-buffered application indicates a frame
is complete with glXSwapBuffers. By default when spoiling is enabled these
frames are treated as 1st class. When glFlush is received a frame is
only generated when the queue is empty (otherwise the last glFlush is spoiled).
Normally this is the desired behaviour, but certain applications like
Ansoft HFSS mix front and backbuffer drawing and rely on glFlush getting
pushed to a frame. By setting VGL_SPOILLASTFLUSH to 0, frames generated
by glFlush are promoted to 1st class and will replace whatever frames are
in the queue.
(Sponsored by Open Text.)
Add support for VGL_SPOILLASTFLUSH (from cvs diff -u4p)
Checked into CVS Head with modifications.