Some dockerfiles for building libv8 on various platforms. Based on Jan Marvin's v8-static script for building V8 on Arch.
Run docker build . -t myv8 in the source dir. If all goes well, the final image has /v8-{version}.tar.xz in the root. Use docker run myv8 and then docker cp to copy it to your system.
Because depot_tools changes all the time, this will probably only work for recent versions of V8. To build an older V8 version, you may have to add a step to checkout an older version of depot_tools. Suitable dependency versions are storted in the DEPS file in the V8 source tree for the version you are building.
V8 pulls in a custom clang++ compiler at build time, so I think the version of g++ on your system doesn't matter. But it should still be using your system libcxx, which is what is important to use the library in your applications.
This is a minimal build without internationalization which results in a single "monolith" static library. Tweak the gn gen command to enable other features.
Building V8 requires a lot of memory, if you get random failures, docker may be running out of memory or disk space.