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

 --- gcc-4.3.4/libffi/src/arm/sysv.S	

 +++ gcc-4.3.4/libffi/src/arm/sysv.S	

 @@ -235,7 +235,7 @@ ARM_FUNC_START ffi_closure_SYSV

  	stmfd	sp!, {ip, lr}

  	UNWIND .save	{r0, lr}

  	add	r2, sp, #8

 -	.pad #16

 +	UNWIND .pad #16

  	sub	sp, sp, #16

  	str	sp, [sp, #8]

  	add	r1, sp, #8