Handle unresolved relocations at link time

Author: mxamin

setup.py

@@ -189,6 +189,13 @@ def run(self):
                     '-fno-strict-aliasing',
                     '-Wno-error=declaration-after-statement',
                     '-Werror=implicit-function-declaration',
+                    '-fvisibility=hidden',
+                    '-fno-common',
+                ]
+            )
+            ext.extra_link_args.extend(
+                [
+                    '-Wl,-Bsymbolic',
                 ]
             )