Fix Neon build error if gcc -O0

[cyb70289]

Fixes#573

[JohanMabille]

Hi,

Sorry for the late reply. Even if I would like to avoid macro as much as possible, it looks like we don't have the choice here, I don't have a better solution to offer.

[cyb70289]

I also don't like macros.
For C++14, a better approach may be defining only one macro to wrap all intrinsics.
#define F(f) [](auto... args){ return f(args...); }
Then we have to change make_tuple(vorrq_u8, vorrq_s8, ...) to make_tuple(F(vorrq_u8), F(vorrq_s8), ...).
Haven't tested, looks it can work.
For C++11, we need to infer function parameter type, should be doable.

[cyb70289]

@JohanMabille@serge-sans-paille
Will you review the PR? Thanks.

[JohanMabille]

Looks very good to me, I like how the code is homogeneous with existing intrinsics and how the same pattern is applied everywhere, it makes the code easy to read and understand.