simd.h fix for gcc8 warnings when sse is disabled (#2130)
simd.h fix for gcc8 warnings when sse is disabled (#2130)

It's now a warning to use memcpy into a class with no trivial constructor.
lgritz/oiio,lgritz/oiio,lgritz/oiio,OpenImageIO/oiio,OpenImageIO/oiio,lgritz/oiio,OpenImageIO/oiio,OpenImageIO/oiio