def METHOD_NAME(self, env):
    env.set("GRPC_PYTHON_BUILD_WITH_CYTHON", True)
    env.set("GRPC_PYTHON_BUILD_SYSTEM_OPENSSL", True)
    env.set("GRPC_PYTHON_BUILD_SYSTEM_ZLIB", True)
    env.set("GRPC_PYTHON_BUILD_SYSTEM_CARES", True)
    env.set("GRPC_PYTHON_BUILD_SYSTEM_RE2", True)
    # https://github.com/grpc/grpc/pull/24449
    env.set("GRPC_BUILD_WITH_BORING_SSL_ASM", "")
    env.set("GRPC_PYTHON_BUILD_EXT_COMPILER_JOBS", str(make_jobs))
    for dep in self.spec.dependencies(deptype="link"):
        query = self.spec[dep.name]
        env.prepend_path("LIBRARY_PATH", query.libs.directories[0])
        env.prepend_path("CPATH", query.headers.directories[0])