Full error log: ./build/external/v8_3.30.33.16-patched_install.log
make[1]: [mk/support/build.mk:149: build/external/v8_3.30.33.16-patched/lib/libv8.a] Error 1
make: [Makefile:53: make] Error 2


Try adding CXX=clang++ to the configure line.
I have made a PR to update the build instructions: https://github.com/rethinkdb/docs/pull/1267
Also, I've added Arch Linux to https://github.com/srh/rethinkdb-package-builder so precise build instructions can also be observed there (or you can use that to run a build for Arch Linux).
I use Clang ++ and it works, thanks for the help