[Rd] Building manuals are failing now that MikTex 2.9 has removed texi2dvi.exe

[Avraham Adler]

According to the MikTex bug reports [1], MikTex 2.9 has removed
texi2dvi.exe last week (on 2015-09-29) as "it was not compatible
(anymore) with the original shell script texi2dvi (GNU Texinfo)." I
found this out the hard way as I just (unknowingly) updated MikTex
this evening, and then, while building R-devel_2015-10-08 on Windows7
64bit using the Rtools 3.3 toolchain (4.9.3 branch), had it crash
during `make manuals` with:

Output written on fullrefman.pdf (3468 pages, 9511515 bytes).
Transcript written on fullrefman.log.
creating doc/manual/version.texi
texi2dvi --pdf --texinfo="@set UseExternalXrefs " R-FAQ.texi
texi2dvi: not found
make[1]: *** [R-FAQ.pdf] Error 127
make: *** [manuals] Error 2

Outside of trying to dig up an old (and now obsolete) version of the
executable, what can be, or should be, done to build the manuals, or
have we lost that ability?

Thank you,

Avi

[1] http://sourceforge.net/p/miktex/bugs/2400/