setup system includes for generated files on MacOS (pytorch#73591)

Summary: Pull Request resolved: pytorch#73591

Test Plan: Imported from OSS

Reviewed By: malfet

Differential Revision: D34558342

Pulled By: dagitses

fbshipit-source-id: 6914a9a95d73105356e7b9c1543deab8bbdeec57
(cherry picked from commit 8b2e338)

.bazelrc

@@ -5,6 +5,7 @@ build --copt=-I.
 # (e.g. c10/macros/cmake_macros.h) by making the generated directory a
 # system include path.
 build --copt=-isystem --copt bazel-out/k8-fastbuild/bin
+build --copt=-isystem --copt bazel-out/darwin-fastbuild/bin
 build --experimental_ui_max_stdouterr_bytes=2048576
 
 # Configuration to disable tty features for environments like CI