SQLite.swift unknown type name 'NS_ASSUME_NONNULL_BEGIN'

Question

I'm using SQLite.swift. There's an error "Unknown type name 'NS_ASSUME_NONNULL_BEGIN'" when I build the project.

What I do:

create a demo project 'SqlDemo'

under SqlDemo/, create Podfile

use_frameworks!

source 'http://git.oschina.net/akuandev/Specs.git'
pod 'SQLite.swift', git:'https://github.com/stephencelis/SQLite.swift.git'
# pod 'SQLite.swift/Cipher', git: ... # instead, for SQLCipher support

~

then 'pod install'

after that open SqlDemo.xcworkspace

build the project

this maybe a pretty simple error. I'm new to ios dev.