aix.S (ffi_call_AIX): Convert to more standard register usage.

aix.S (ffi_call_AIX): Convert to more standard register usage.

        * src/powerpc/aix.S (ffi_call_AIX): Convert to more standard
        register usage.  Call ffi_prep_args directly.  Add long double
        return value support.
        * src/powerpc/ffi_darwin.c (ffi_prep_args): Double arg increment
        applies to FFI_TYPE_DOUBLE.  Correct fpr_base increment typo.
        Separate FFI_TYPE_SINT32 and FFI_TYPE_UINT32 cases.
        (ffi_prep_cif_machdep): Only 16 byte stack alignment in 64 bit
        mode.
        (ffi_closure_helper_DARWIN): Remove nf and ng counters.  Move temp
        into case.
        * src/powerpc/aix_closure.S: Maintain 16 byte stack alignment.
        Allocate result area between params and FPRs.

From-SVN: r154892