The "attach-debugger" option is broken on the current master branch.

[JiakunYan]

Expected Behavior

The option is accepted by HPX.

Actual Behavior

HPX complaint

hpx::init: exception caught: Unknown/misspelled HPX command line option found: --hpx:attach-debugger=startup

Steps to Reproduce the Problem

1. Compile the current master branch.
2. Run ./fibonacci_futures_distributed --hpx:attach-debugger=startup

Specifications

• HPX Version: The current master branch 734d37f039ca00338fff4711aba7804fb1e778a0
• Platform (compiler, OS): Ubuntu 20.04. GCC 9.4.

[JiakunYan]

The related code are pasted below.

#if defined(_POSIX_VERSION) || defined(HPX_WINDOWS)
            ("hpx:attach-debugger",
                value<std::string>()->implicit_value("startup"),
                "wait for a debugger to be attached, possible values: "
                "off, startup, exception or test-failure (default: startup)")
#endif

It seems _POSIX_VERSION never got defined because unistd.h isn't included when compiling that file.