Detect: Fix GNU builtin include directory detection on aarch64
Detect: Fix GNU builtin include directory detection on aarch64

There is no `emmintrin.h` or `altivec.h` header for this architecture,
so use `arm_neon.h` instead.

bradking/CastXML,CastXML/CastXML,bradking/CastXML,bradking/CastXML,ellert/CastXML,CastXML/CastXML,ellert/CastXML,CastXML/CastXML,ellert/CastXML