Add docs for issue #255

docs/src/faq.md

@@ -11,3 +11,27 @@ Python(65251,0x104cf8580) malloc: *** set a breakpoint in malloc_error_break to
 ```
 
 A solution is to ensure that `juliacall` is imported before `torch`.
+
+## `ccall requries the compiler` error when importing some Python libraries
+On some systems, you may see an error like the following when import e.g. `matplotlib` before `juliacall`:
+
+```
+ERROR: `ccall` requires the compilerTraceback (most recent call last):
+  File "/home/dingraha/projects/pythoncall_import_error/run.py", line 2, in <module>
+    from foo import Foo
+  File "/home/dingraha/projects/pythoncall_import_error/foo.py", line 4, in <module>
+    import juliacall; jl = juliacall.newmodule("FooModule")
+  File "/home/dingraha/projects/pythoncall_import_error/venv/lib/python3.9/site-packages/juliacall/__init__.py", line 218, in <module>
+    init()
+  File "/home/dingraha/projects/pythoncall_import_error/venv/lib/python3.9/site-packages/juliacall/__init__.py", line 214, in init
+    raise Exception('PythonCall.jl did not start properly')
+Exception: PythonCall.jl did not start properly
+```
+
+As described in [issue 255](https://github.com/cjdoris/PythonCall.jl/issues/255), the likely problem is that the "other" Python library (`matplotlib`, whatever) is loading the system `libstdc++.so`, which isn't compatible with the `libstdc++.so` that Julia ships with.
+Linux distributions with older `libstdc++` versions seem more likely to suffer from this issue.
+The solution is to either:
+
+  * use a Linux distribution with a more recent `libstdc++`
+  * import `juliacall` before the other Python library, so that Julia's `libstdc++` is loaded
+  * use a Python from a conda environment, which will have a newer `libstdc++` that is compatible with Julia's