Set module name for Spam/__init__.pyx to Spam.

Cython/Compiler/Symtab.py

@@ -805,7 +805,12 @@ class ModuleScope(Scope):
         self.parent_module = parent_module
         outer_scope = context.find_submodule("__builtin__")
         Scope.__init__(self, name, outer_scope, parent_module)
-        self.module_name = name
+        if name != "__init__":
+            self.module_name = name
+        else:
+            # Treat Spam/__init__.pyx specially, so that when Python loads
+            # Spam/__init__.so, initSpam() is defined.
+            self.module_name = parent_module.module_name
         self.context = context
         self.module_cname = Naming.module_cname
         self.module_dict_cname = Naming.moddict_cname