Bug: std::call_once pthreads linking issue

[Steven-Roberts]

Description how to reproduce the bug

$ ./DynamicSimulation hawaii.case.json 
terminate called after throwing an instance of 'std::system_error'
  what():  Unknown error -1
Aborted

GridKit™ version

develop branch

System and environment details

RHEL using these spack packages

- llvm@20.1.8
- enzyme@0.0.206
- sundials@develop~mpi+klu logging-level=4

Additional information

GDB shows the exception is raised here.

GridKit/GridKit/Model/PhasorDynamics/Exciter/IEEET1/Ieeet1Impl.hpp

Lines 556 to 557 in de7bea1

	std::call_once(time_constant_warning_flag_,
	&logTimeConstantWarning);

It seems pthreads wasn't linked, so it can't call std::call_once. It's unclear if this is a quirk of my build environment or a legitimate build issue.

[nkoukpaizan]

Looks like std::call_once depends on pthreads on linux. It just so happens that the systems I'm using secretly make it available. I'd rather not require linking to Threads. @Steven-Roberts I'll work on a fix. Do you have a way to workaround this?

[Steven-Roberts]

Thanks! I can manually set the linking flags in the meantime.