support using external dependencies from pkgconf

[selfisekai]

What is the problem this feature would solve?

requirement of many distros for distribution packaging. example policy from gentoo: https://wiki.gentoo.org/wiki/Why_not_bundle_dependencies

What is the feature you are proposing to solve the problem?

implement an option to use pkg-config for providing dependencies:

• base64
• boringssl (allow using openssl?)
• c-ares
• libarchive
• lolhtml
• mimalloc
• picohttp
• sqlite
• tinycc
• usockets
• uws
• zlib
• zstd

pkg-config returns flags for dependencies as needed, e.g. on my system:

$ pkg-config --libs --cflags zlib   
 -L/lib -lz

simply, don't ensure dependencies are built as expected in your current workflow, and get the needed flags from pkg-config.

What alternatives have you considered?

No response