Cameron Hart

This did start out as a macro as it is in C but I couldn't work out how to declare it in coresimd and rexport it to stdsimd. So I'm...

Yep sure.

I also reproduced it on Windows running in a VM on Linux if that's any help.

The test still seems to be failing on Windows with changes in ddddadf.

I've done some investigation into this. I think the problem is uninitialized variables on execution_plan. In particular the warmup_time member which is of type std::chrono::nanonseconds. If I print that out...

OK, looking at the documentation on MSDN this is expected behaviour - the default constructed value is uninitialized - https://msdn.microsoft.com/en-us/library/hh874737.aspx?f=255&MSPPError=-2147217396 edit: it's strange that this is fine on Linux but...

Continuing my novella on this topic; I discovered that these uninitialised variables are reported when I run `valgrind ./bin/test` on Linux.

I've found a problem with my optional implementation under MSVC, so will close this PR until I manage to resolve it.

Addressed issues with optional.

Yep, I think it should fix #48 :)