genbindings: add new AllowCtor framework

cmd/genbindings/clang2il.go

@@ -394,6 +394,10 @@ nextMethod:
 			// an existing class instance
 			mm.IsStatic = true
 
+			if !AllowCtor(ret.ClassName, mm) {
+				continue
+			}
+
 			ret.Ctors = append(ret.Ctors, mm)
 
 		case "CXXDestructorDecl":

cmd/genbindings/config-allowlist.go

@@ -321,6 +321,12 @@ func AllowMethod(className string, mm CppMethod) error {
 	return nil // OK, allow
 }
 
+func AllowCtor(className string, mm CppMethod) bool {
+
+	// Default allow
+	return true
+}
+
 // AllowType controls whether to permit binding of a method, if a method uses
 // this type in its parameter list or return type.
 // Any type not permitted by AllowClass is also not permitted by this method.