toolchain: Clippy Linting sets ENABLE_RUST_CLIPPY

This CL adds support for enabling Cargo Clippy for Rust CLs by
environment variable at runtime by modifying make.conf in the sysroot.
This is allows the build_linters recipe to work without the Clippy
portage profile for Atlas and is part of an effort to prevent linting
from taking place during the install packages step. This also updates
the call_template to reflect the removal of trace_events in test data.

BUG=b:191687433
TEST=CQ and call_scripts

Change-Id: I0f0e72375ac630f31c6ae396a69caa78e4d65a21
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2998785
Tested-by: Ryan Beltran <ryanbeltran@chromium.org>
Commit-Queue: Ryan Beltran <ryanbeltran@chromium.org>
Reviewed-by: Alex Klein <saklein@chromium.org>
diff --git a/api/controller/toolchain.py b/api/controller/toolchain.py
index 00b412a..3693646 100644
--- a/api/controller/toolchain.py
+++ b/api/controller/toolchain.py
@@ -12,6 +12,7 @@
 from chromite.api.controller import controller_util
 from chromite.api.gen.chromite.api import toolchain_pb2
 from chromite.api.gen.chromiumos.builder_config_pb2 import BuilderConfig
+from chromite.lib import cros_build_lib
 from chromite.lib import cros_logging as logging
 from chromite.lib import toolchain_util
 from chromite.lib import chroot_util
@@ -381,11 +382,11 @@
 @validate.validation_complete
 def GetClippyLints(input_proto, output_proto, _config):
   """Emerges the given packages and retrieves any findings from Cargo Clippy."""
-  chroot_util.Emerge(
-      [package.package_name for package in input_proto.packages],
-      sysroot=input_proto.sysroot.path,
-      with_deps=False,
-      rebuild_deps=True,
-      # TODO(b/188590586): consider setting jobs to emerge in parallel
+  emerge_cmd = chroot_util.GetEmergeCommand(input_proto.sysroot.path)
+  package_names = [package.package_name for package in input_proto.packages]
+  cros_build_lib.sudo_run(
+    emerge_cmd + package_names,
+    preserve_env=True,
+    extra_env={'ENABLE_RUST_CLIPPY':1}
   )
   output_proto.findings.extend(_fetch_clippy_lints())