allow user to configure opt_handle_signals (#333)

* allow user to configure opt_handle_signals

* update FAQ

* revert to single-quote syntax

Author: brian-dellabetta

docs/src/faq.md

@@ -9,6 +9,11 @@ Some rules if you are writing multithreaded code:
 - You probably also need to call `PythonCall.GC.disable()` on the main thread before any
   threaded block of code. Remember to call `PythonCall.GC.enable()` again afterwards.
   (This is because Julia finalizers can be called from any thread.)
+- Julia intentionally causes segmentation faults as part of the GC safepoint mechanism.
+  If unhandled, these segfaults will result in termination of the process. To enable signal handling,
+  set `PYTHON_JULIACALL_HANDLE_SIGNALS=yes` before any calls to import juliacall. This is equivalent
+  to starting julia with `julia --handle-signals=yes`, the default behavior in Julia. 
+  See discussion [here](https://github.com/cjdoris/PythonCall.jl/issues/219#issuecomment-1605087024) for more information.
 - You may still encounter problems.
 
 Related issues: [#201](https://github.com/cjdoris/PythonCall.jl/issues/201), [#202](https://github.com/cjdoris/PythonCall.jl/issues/202)

pysrc/juliacall/__init__.py

@@ -129,7 +129,7 @@ def args_from_config():
     CONFIG['opt_sysimage'] = sysimg = path_option('sysimage', check_exists=True)[0]
     CONFIG['opt_threads'] = int_option('threads', accept_auto=True)[0]
     CONFIG['opt_warn_overwrite'] = choice('warn_overwrite', ['yes', 'no'])[0]
-    CONFIG['opt_handle_signals'] = 'no'
+    CONFIG['opt_handle_signals'] = choice('handle_signals', ['yes', 'no'], default='no')[0]
 
     # Stop if we already initialised
     if CONFIG['inited']: