Clean cppclass <init> management

Cython/Compiler/PyrexTypes.py

@@ -4030,7 +4030,10 @@ class CppClassType(CType):
                 break
 
         func_type = CFuncType(self, [], exception_check='+', nogil=nogil)
-        return self.scope.declare_cfunction(u'<init>', func_type, pos)
+        entry = self.scope.declare_cfunction(u'<init>', func_type, pos)
+        # This flag is set in order to be able to override this default __init__ by a user-defined one
+        entry.is_inherited = 1
+        return entry
 
     def check_nullary_constructor(self, pos, msg="stack allocated"):
         constructor = self.scope.lookup(u'<init>')

Cython/Compiler/Symtab.py

@@ -485,11 +485,7 @@ class Scope(object):
             if type.is_cfunction and old_entry.type.is_cfunction and self.is_cpp_class_scope:
                 for index, alt_entry in enumerate(old_entry.all_alternatives()):
                     if type.compatible_signature_with(alt_entry.type):
-                        if name == '<init>' and not type.args:
-                            # Cython pre-declares the no-args constructor - allow later user definitions.
-                            old_index = index
-                            cpp_override_allowed = True
-                        elif alt_entry.is_inherited:
+                        if alt_entry.is_inherited:
                             old_index = index
                             cpp_override_allowed = True
                         break