Extension components header files not found

[jackhschwartz]

Here is the Xcode:
// NotificationService.h
// com.passportcorp.workshop.push.NotificationSvc
// Created by Jack Schwartz on 10/7/16.
// JHS as per: https://go.urbanairship.com/apps/ZAvgvDsWSUODNzX8PVUhog/quickstart_guide/ step 9.

import <AirshipAppExtensions/AirshipAppExtensions.h> //<-- file not found!

@interface NotificationService : UAMediaAttachmentExtension
@EnD

Here are the Header Search Paths:
"$(TARGET_BUILD_DIR)/usr/local/lib/include"
"$(OBJROOT)/UninstalledProducts/$(PLATFORM_NAME)/include"
"$(BUILT_PRODUCTS_DIR)"