Restructure the ifdef ladder, separating 64-bit from 32-bit,
and ensure _CALL_AIX is set for ELF v1. Fixes the build for
ppc64 big-endian host with clang.
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
dc8a8cc879