The only enabling configuration of this is irreproducible. Since
terminfo doesn't provide essential functionality, remove it so that all
external dependencies now follow the same config_setting pattern.
This should be an NFC for most setups and all CI setups.
Reviewed By: phosek, MaskRay
Differential Revision: https://reviews.llvm.org/D151006
Only require one intermediate repository instead of two.
Fewer parameters in llvm_config.
Second attempt of https://reviews.llvm.org/D107714, this time also updating `third_party_build` and `deps_impl` paths.
Reviewed By: GMNGeoffrey
Differential Revision: https://reviews.llvm.org/D108274
