bootstrap: check local_rebuild before adding --cfg=bootstrap, closes #84057
bootstrap: check local_rebuild before adding --cfg=bootstrap, closes #84057

aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust