#4736 Add XeTeX @image support to texinfo.tex

[Masamichi Hosoda]

Add XeTeX @image support to texinfo.tex

http://lists.gnu.org/archive/html/bug-texinfo/2016-01/msg00060.html
The patch should be merged into Texinfo but has not yet been merged.

This patch requires Issue 4735.
https://sourceforge.net/p/testlilyissues/issues/4735/

http://codereview.appspot.com/286740043

[Anonymous]

Passes make, make check and a full make doc.

Tested when combined with:

https://sourceforge.net/p/testlilyissues/issues/4729/
https://sourceforge.net/p/testlilyissues/issues/4731/
https://sourceforge.net/p/testlilyissues/issues/4732/
https://sourceforge.net/p/testlilyissues/issues/4733/
https://sourceforge.net/p/testlilyissues/issues/4734/
https://sourceforge.net/p/testlilyissues/issues/4735/
https://sourceforge.net/p/testlilyissues/issues/4736/

[Masamichi Hosoda]

I'll change this patch status to needs_work.
https://sourceforge.net/p/testlilyissues/issues/4737/

[Masamichi Hosoda]

This patch is already merged into Texinfo.
Issue 4735 includes XeTeX @image support.
https://sourceforge.net/p/testlilyissues/issues/4735/