arch/powerpc: add powerpc64le support

Technically, I don't forbid powerpcle support either, but I'm not sure that
there is any library/compiler support for that at the moment (though the hw
technically makes it possible).

powerpc64le needs glibc 2.19 and gcc 4.9. I haven't looked into the support
tools, but at least gdb 7.5 is too old (7.7.1 definitely has support).

Also make powerpc64 non-experimental. It's practically old at this point.

Signed-off-by: Cody P Schafer <dev@codyps.com>
[yann.morin.1998@free.fr: use ${target_endian_le} and ${target_bits_64}]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <64bfbbced9dd8f62e0d6.1399801945@gun>
Patchwork-Id: 347775

diff -durN ltrace-0.4.orig/configure ltrace-0.4/configure

--- ltrace-0.4.orig/configure	2008-10-23 23:19:38.000000000 +0200

+++ ltrace-0.4/configure	2008-10-23 23:19:06.000000000 +0200

@@ -1392,6 +1392,9 @@

 HOST_OS="$host_os"

+case "${HOST_OS}" in

+  linux-*) HOST_OS=linux-gnu;;

+esac

 ac_ext=c

diff -durN ltrace-0.4.orig/configure.ac ltrace-0.4/configure.ac

--- ltrace-0.4.orig/configure.ac	2008-10-23 23:19:43.000000000 +0200

+++ ltrace-0.4/configure.ac	2008-10-23 23:18:44.000000000 +0200

@@ -7,6 +7,9 @@

 dnl Check host system type

 AC_CANONICAL_HOST

 HOST_OS="$host_os"

+case "${HOST_OS}" in

+  linux-*) HOST_OS=linux-gnu;;

+esac

 AC_SUBST(HOST_OS)

 dnl Checks for programs.