Pod 명령 실행 시 Ignoring xxx because its extensions are not built 에러 대응 (feat. rbenv)

pod --version
Ignoring ffi-1.13.1 because its extensions are not built. Try: gem pristine ffi --version 1.13.1
Ignoring json-2.5.1 because its extensions are not built. Try: gem pristine json --version 2.5.1
Ignoring json-2.5.0 because its extensions are not built. Try: gem pristine json --version 2.5.0
Ignoring json-2.3.0 because its extensions are not built. Try: gem pristine json --version 2.3.0
Ignoring json-2.5.1 because its extensions are not built. Try: gem pristine json --version 2.5.1
Ignoring json-2.5.0 because its extensions are not built. Try: gem pristine json --version 2.5.0
Ignoring json-2.3.0 because its extensions are not built. Try: gem pristine json --version 2.3.0
Ignoring json-2.5.1 because its extensions are not built. Try: gem pristine json --version 2.5.1
Ignoring json-2.5.0 because its extensions are not built. Try: gem pristine json --version 2.5.0
Ignoring json-2.3.0 because its extensions are not built. Try: gem pristine json --version 2.3.0
Ignoring json-2.5.1 because its extensions are not built. Try: gem pristine json --version 2.5.1
Ignoring json-2.5.0 because its extensions are not built. Try: gem pristine json --version 2.5.0
Ignoring json-2.3.0 because its extensions are not built. Try: gem pristine json --version 2.3.0
Ignoring json-2.5.1 because its extensions are not built. Try: gem pristine json --version 2.5.1
Ignoring json-2.5.0 because its extensions are not built. Try: gem pristine json --version 2.5.0
Ignoring json-2.3.0 because its extensions are not built. Try: gem pristine json --version 2.3.0
Ignoring json-2.5.1 because its extensions are not built. Try: gem pristine json --version 2.5.1
Ignoring json-2.5.0 because its extensions are not built. Try: gem pristine json --version 2.5.0
Ignoring json-2.3.0 because its extensions are not built. Try: gem pristine json --version 2.3.0
Ignoring json-2.5.1 because its extensions are not built. Try: gem pristine json --version 2.5.1
Ignoring json-2.5.0 because its extensions are not built. Try: gem pristine json --version 2.5.0

rbenv 환경에서 pod 명령 실행 시 위와 같은 에러가 발생하는 경우 대응 방법

1. rbenv 를 system 기본 버전으로 설정
2. Try: 에서 제안하는 명령어를 sudo 에서 line 단위로 실행

> sudo gem pristine ffi --version 1.13.1