Issue 774 on ARM

[beewoolie]

Issue 774 on ARM

[grisumbras]

This appears to be another problem with detection of platform features on MacOS. @pdimov can you look into it?

[grisumbras]

Just to be sure, have you tried any of the workarounds mentioned in #774 ?

[pdimov]

I suppose this is again caused by BOOST_NO_CXX11_HDR_MUTEX being defined by Boost.Config for this platform, but I've no idea why that is.

Is libstdc++ compiled as single-threaded?

[beewoolie]

Likely. These are arm-none-eabi targets, no OS, single core, so there isn't going to be a need for threading.

I don't have a working sample anymore since I had to move on. I don't have a way to test the boost JSON code and compiler switches.

FWIW, nlohmann's library links and it doesn't require additional code when we disable exceptions. Perhaps at a later date we can return to this detail and determine whether or not the boost library is a better long-term component.

[pdimov]

In that case, the solution is to define the macro BOOST_SYSTEM_DISABLE_THREADS.