debug/gdb: fix from upstream with newer glibc(siginfo vs siginfo_t, Gentoo gdb-7.4.1 patch)

This is for when you failed to build gdb-native with the error:

gdb-7.4.1/gdb/linux-nat.h:79:18: error: field 'siginfo' has incomplete type"

This is from mirror://gentoo/distfiles/gdb-7.4.1-patches-2.tar.xz

Signed-off-by: "Jang, Bongseo" <graycells@gmail.com>
[yann.morin.1998@free.fr: refresh ptrace_setsiginfo patch]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-ID: <4eef2edec3201c50b420.1348370891@localhost.localdomain>
PatchWork-ID: 186179

 # Dummy config file to not use a C library *at all*

 ## depends on BARE_METAL

 ##

 ## help Do not use a C library.

 ## help

 ## help This is usefull if your project is self-contained, does not rely on

 ## help an external C library, and provides all the necessary bits.

 ## help

 ## help Most probably usefull to bootloaders, as they generally don't depend

 ## help on the C library.

 ## help

 ## help If unsure: do *not* choose that, and use another option in the choice.