The sources for x86_64 are shared in the i386 directory which will be
included thanks to TARGET_BASE_ARCH. However not all sources build so
we need to filter out the ones we can't build in the 64 bit world and
those that can't be built for 32 bit.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
