ios ld: symbol(s) not found for

添加libresolv.tbd库，即可解决问题

Undefined symbols for architecture arm64:

"_dns_parse_resource_record", referenced from:

  -[JPUSHSRVResolver processRecord:length:] in jpush-iOS-2.2.0.a(JPUSHSRVResolver.o)

"_dns_free_resource_record", referenced from:

  -[JPUSHSRVResolver processRecord:length:] in jpush-ios-2.2.0.a(JPUSHSRVResolver.o)

ld: symbol(s) not found for architecture arm64

clang: error: linker command failed with exit code 1 (use -v to see invocation)