How to build own v8 fork

[Simon Koch]

I have forked the v8 repository and made some changes. Now I want to build it.

However, I cannot find any documentation concerning this use case.

Every documentation starts with using fetch, however, fetch does not offer the option to use your own repository.

Using gclient or gn results in the error message that I need to check out.

[Ben Noordhuis]

gclient is for fetching V8 and its dependencies but once you have that
set up (and have a version of depot_tools checked out and on your
PATH), you can configure your fork with tools/dev/gm.py and build with
ninja.

If you have an existing fork, try fetching upstream V8 first, then
merging in the changes from your fork with `git pull` / `git merge`.