Figure out a way to support and pass through configs

llvm toolchains have powerful config file support.

many of the llvm toolchain builds have support for those (todo check which, or add one if there isn't one).

it would be very useful for integration with hardening build flags to support passing through and using the user or project provided llvm toolchain config flags.

this is specifically to better support "distro toolchain" configs, without needing to use the system built llvm toolchain; but instead enable one to pass through opinionated llvm toolchain configs.

This issue is vague for now, but will experiment with a few options to refine this ask more.

The issue names no files, tests, or entry points. Start by checking which LLVM toolchain builds support config files and comparing options for passing user- or project-provided configs through the toolchain. Done means a defined approach for supporting distro toolchain configs, with its scope and validation steps documented.

Written by the indexing model from the issue text.