update docs

Author: oraluben

docs/advanced/exceptions.rst

@@ -164,6 +164,9 @@ section.
     may be explicitly (re-)thrown to delegate it to the other,
     previously-declared existing exception translators.
 
+    Libc++ `behaves differently <https://stackoverflow.com/questions/19496643/using-clang-fvisibility-hidden-and-typeinfo-and-type-erasure/28827430>`_
+    with ``-fvisibility=hidden``. So you'll need to explicitly export exceptions who'll be used across ABI boundaries as ``tests/test_exceptions.h``.
+
 .. _handling_python_exceptions_cpp:
 
 Handling exceptions from Python in C++