Some distros (ubuntu 16.10, debian-testing) default to gcc configured with
--enable-default-pie (see gcc -v). This breaks e.g. prelink-native on a pie
default system if binutils-native was built on a system which is not pie default
We therefore enable pie unconditionally for native recipes where static libs are
used such as libiberty from binutils, for now, until our minimum distro set is
all default pie.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

Create a common include file for compiler flags which allow native binaries to
be interoperable on a wide range of hosts. In particular the C++ ABI is
problematic so choose the CXX11 version to allow interoperation between gcc4 and
gcc5 based hosts. Moving this to a common include instead of uninative.bbclass
allows uninative to be configured later and used in the eSDK (where its
mandatory) even if the base configuration doesn't enable uninative by default
(e.g. nodistro in OE-Core).

[ YOCTO #10645 ]

Signed-off-by: Ross Burton <ross.burton@intel.com>