`No such file or directory: './v8/DEPS'` error when trying to build from source on Windows

[TheJanzap]

I tried to build rusty_v8 on Windows from source, but it fails when trying to open the nonexisting DEPS file in a Python file.

> git log -n 1        
commit 5c15a6995c9bb4bacd3e341b59fff32c909c80bf (HEAD -> main, origin/main, origin/HEAD)
Author: Bartek Iwańczuk <biwanczuk@gmail.com>
Date:   Fri Jul 24 23:53:38 2026 +0200

    v150.4.0 (#2030)
> python --version         
Python 3.14.6
> $env:V8_FROM_SOURCE=1
> cargo build -vv
# [snip]
  --- stderr
  Traceback (most recent call last):
    File "C:\git\rusty_v8\tools\ninja_gn_binaries.py", line 15, in <module>
      from v8_deps import Var
    File "C:\git\rusty_v8\tools\v8_deps.py", line 6, in <module>
      with open('./v8/DEPS') as f:
           ~~~~^^^^^^^^^^^^^
  FileNotFoundError: [Errno 2] No such file or directory: './v8/DEPS'

  thread 'main' (12008) panicked at build.rs:637:5:
  assertion failed: Command::new(python()).arg("./tools/ninja_gn_binaries.py").arg("--dir").arg(&target_dir).status().unwrap().success()
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...

How can I fix this?