Bug#823519: GCC 4.9 missing ARM and Neon Intrinsics for AARCH64

[Jeffrey Walton <noloader@gmail.com>]

This is also kind of interesting in a morbid sort of way:

    $ cpp -dM </dev/null | grep -i arm
    #define __ARM_NEON 1

According to http://infocenter.arm.com/help/topic/com.arm.doc.ihi0053c/IHI0053C_acle_2_0.pdf,
Section 12.1, __ARM_NEON is defined when ARM Neon Intrinsics are
available:

    NEON intrinsics are available if the __ARM_NEON macro is predefined
    (see 6.5.4), but in order to access NEON intrinsics it is necessary to
    include the <arm_neon.h> header.

Jeff