Hi,

on Fedora Rawhide==F-29 PDF build fails with:
	https://kojipkgs.fedoraproject.org//work/tasks/2102/26052102/build.log
	texi2dvi --pdf  -I ../../../gdb/doc/../mi -I ../../../gdb/doc \
		../../../gdb/doc/gdb.texinfo
	! I can't find file `texinfo.tex'.

TBH I do not see how the file could be found in earlier versions.  Also both
F-29 and F-28 have texinfo-tex-6.5-3.fc28.x86_64 while in F-28 it still builds
fine but in F-29 it does not - so apparently it depends on some other package.

But I did not investigate why as IMO the patch below is a logical one.

OK for check-in?


Jan