This relands #167348.
The original PR was reverted due to a reported build failure, which was
later diagnosed as a local issue in the developer’s checkout or build
state. See discussion here:
https://github.com/llvm/llvm-project/pull/163659#discussion_r2511546964
No additional changes have been made in this reland.
This change moves option-related code from clangDriver into a new
clangOptions library.
This refactoring is part of a broader effort to support driver-managed
builds for compilations using C++ named modules and/or Clang modules.
It is required for linking the dependency scanning tooling against the
driver without introducing cyclic dependencies, which would otherwise
cause build failures when dynamic linking is enabled.
In particular, clangFrontend must no longer depend on clangDriver
for this to be possible.
This PR is motivated by the following review comment:
https://github.com/llvm/llvm-project/pull/152770#discussion_r2430756918
