Many examples do not link with Git HEAD version

[jewillco]

When trying to build examples, many of them produce errors such as:

CMakeFiles/hello_world_exe.dir/hello_world.cpp.o: In function `(anonymous namespace)::hpx_plugin_exporter_factory_HPX_COMPONENT_NAME_hello_world_foreman_action::hpx_plugin_exporter_factory_HPX_COMPONENT_NAME_hello_world_foreman_action()':
hello_world.cpp:(.text+0x10f6): undefined reference to `hpx_exported_plugins_list_HPX_COMPONENT_NAME_factory'               
CMakeFiles/hello_world_exe.dir/hello_world.cpp.o: In function `(anonymous namespace)::hpx_plugin_exporter_registry_HPX_COMPONENT_NAME_hello_world_worker_action::hpx_plugin_exporter_registry_HPX_COMPONENT_NAME_hello_world_worker_action()':
hello_world.cpp:(.text+0x1276): undefined reference to `hpx_exported_plugins_list_HPX_COMPONENT_NAME_registry'               
CMakeFiles/hello_world_exe.dir/hello_world.cpp.o: In function `(anonymous namespace)::hpx_plugin_exporter_factory_HPX_COMPONENT_NAME_hello_world_worker_action::hpx_plugin_exporter_factory_HPX_COMPONENT_NAME_hello_world_worker_action()':
hello_world.cpp:(.text+0x13f6): undefined reference to `hpx_exported_plugins_list_HPX_COMPONENT_NAME_factory'               
CMakeFiles/hello_world_exe.dir/hello_world.cpp.o: In function `_GLOBAL__sub_I_hello_world.cpp':
hello_world.cpp:(.text.startup+0x30f): undefined reference to `hpx_exported_plugins_list_HPX_COMPONENT_NAME_registry'        
collect2: error: ld returned 1 exit status
make[3]: *** [bin/hello_world] Error 1
make[3]: Target `examples/quickstart/CMakeFiles/hello_world_exe.dir/build' not remade because of errors.
make[2]: *** [examples/quickstart/CMakeFiles/hello_world_exe.dir/all] Error 2

[hkaiser]

Jeremiah, thanks for reporting this, we're aware of this issue (whic I introduced yesterday while trying to catch wrong usage of certain macros as you did). I'm working on finding a compromise.

[jewillco]

When I define HPX_COMPONENT_NAME in my code and add the call to HPX_REGISTER_COMPONENT_MODULE(); back in, it links but I get seg faults at run-time (in cp-demangle.c).

[hkaiser]

You should never need to use HPX_REGISTER_COMPONENT_MODULE(); in an executable.

[jewillco]

Adding it and defining HPX_COMPONENT_NAME seems to be what makes the executables link; removing it causes linker errors from missing symbols.

[hkaiser]

That's fixed by 5f71a10