grep: Add patch for texinfo 5.1

(From OE-Core master rev: bc6258f88705b0e7989089a8666ac5e5d2355823)

Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
guile: fix build with Texinfo 5.0

Backport a patch from upstream which fixes failures building
guile-native on newer distros such as Ubuntu 13.10. (This does not
affect dora or master because we are using Guile 2.0.9 there, which
already contains this patch.)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>