(https://bugs.freedesktop.org/attachment.cgi?id=2404) Improve rendering
performance when glXSwapBuffers()| or |XPutImage()| are called for the
PostScript DDX via optimizing the codepath around
|PsOut_OutImageBytes()|. Patch by Simon Toedt <simon.toedt@gmail.com>
and Roland Mainz <roland.mainz@nrubsig.org>.
producing spurious characters in PS output when using the bitmap cache
(Originally reported against Solaris Xprt as Sun bug id #4369307, and
fixed in Solaris by Jay Hobson.
visuals to the Postscript DDX (8bit GrayScale/StaticGray, 1bit
StaticGray and the basic infratructure for "deep" visuals with more
than 8bits per RGB gun).