Disable C++ exception handling

Update GCC compiler options to disable C++ exception handling altogether.
Also disable the create of stack unwinding tables since these will not be
required without exceptions enabled.

Author: jedludlow

pymc3/__init__.py

@@ -82,10 +82,16 @@ def __set_compiler_flags():
     # Workarounds for Theano compiler problems on various platforms
     current = theano.config.gcc__cxxflags
     augmented = f"{current} -Wno-c++11-narrowing"
+
     # Work around compiler bug in GCC < 8.4 related to structured exception
     # handling registers on Windows.
     # See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65782 for details.
-    augmented = f"{augmented} -fno-asynchronous-unwind-tables"
+    # First disable C++ exception handling altogether since it's not needed
+    # for the C extensions that we generate.
+    augmented = f"{augmented} -fno-exceptions"
+    # Now disable the generation of stack unwinding tables.
+    augmented = f"{augmented} -fno-unwind-tables -fno-asynchronous-unwind-tables"
+
     theano.config.gcc__cxxflags = augmented