if ((!$venv_built) and (-d $python_src) and can_run("virtualenv")) {
shell_or_die("virtualenv", "--quiet", "--system-site-packages",
"--python=python2.7", $venv_dir);
- shell_or_die("$venv_dir/bin/pip", "--quiet", "install", $python_src);
+ shell_or_die("$venv_dir/bin/pip", "--quiet", "install", "-I", $python_src);
$venv_built = 1;
$Log->("Built Python SDK virtualenv");
}