docs: manual 3rdparty deps management / help

[Alexander Gallego]

Hi All, 

New to v8 src 

Looking at  the docs https://v8.dev/docs/source-code . I am looking for documentation pointers for replacing all 3rdparty libs for my own - meaning, I have them checked out on my filesystem but built at specific hashes/commits.

Is there a guide or post somewhere from someone embedding v8 in a larger project that already has a custom (clang) libcxx, gbenchmark, gtest, lzma, libcxxabi  - what are good docs pointer to look around for. 

I saw ./build/config/BUILD.gn only has support for use_custom_libcxx only, but not sure what is required for the rest. 

I am looking to test out the wasm api only (pointing it out in case there is a way to build less code). 

My project already has a large number of the deps satisfied. The others, I'd like to also build myself and control what gets picked up. I saw on the github repo that most README.v8 have no changes from upstream anyway.

At a high level, it would be great to know 2 things.

1. Min requirement for builds without tests/benchmarks,etc only what is required to build a libv8.a 

1.1 I would then chase the deps and build them myself and put it in a common path for v8 build to pick it up

2. How to pass flags  so the build system doesn't fetch them/build them but instead picks them up. 

Thank you for your help. 

.alex