--hpx:help triggers unusual error with clang build

[biddisco]

hello world gives error when --hpx:help is used and when hpx is compiled with clang.
most unusual.

bin/hello_world --hpx:help
... usual help output is dumped here ...
terminating with uncaught exception of type std::__1::system_error: recursive_mutex lock failed: Invalid argument
Aborted (core dumped)

[kleinhenz]

I am also getting this error on macOS with clang 5.0.0

[hkaiser]

Does this happen in Debug as well? Would it be possible to pinpoint the recursive_mutex instance it's complaining about?

[kleinhenz]

I get the same error in the Debug build of hpx but unfortunately the error does not appear when run in lldb so I wasn't able to get a backtrace.