Work around Cython 3.1.2 non-static internal function bug

Cython recently added __pyx_CommonTypesMetaclass_get_module() but
neglected to make it static; cf cython/cython#6957. Remove it from
the lists of defined symbols to be checked for collisions.

Also ensure that we only strip one leading underscore on macOS,
so that this function's name is as expected.

Author: jmarshall

setup.py

@@ -99,11 +99,14 @@ def run_nm_defined_symbols(objfile):
         if symtype not in "UFNWw":
             if IS_DARWIN:
                 # On macOS, all symbols have a leading underscore
-                symbols.add(sym.lstrip('_'))
+                symbols.add(sym[1:] if sym.startswith("_") else sym)
             else:
                 # Ignore symbols such as _edata (present in all shared objects)
                 if sym[0] not in "_$.@": symbols.add(sym)
 
+    # Work around Cython 3.1.2 bug whereby this function is not static
+    symbols.discard("__pyx_CommonTypesMetaclass_get_module")
+
     return symbols