Use the $GO_GENRULE_EXECROOT env var set by go_genrule

pkg/generated/openapi/def.bzl

@@ -36,17 +36,16 @@ def openapi_library(name, tags, srcs, go_prefix, vendor_prefix = "", openapi_tar
         # All of bazel's $(location)s are relative to the original working directory, however,
         # so we must save it first.
         cmd = " ".join([
-            "ORIG_WD=$$(pwd);",
             "cd $$GOPATH/src/" + go_prefix + ";",
-            "$$ORIG_WD/$(location //vendor/k8s.io/kube-openapi/cmd/openapi-gen)",
+            "$$GO_GENRULE_EXECROOT/$(location //vendor/k8s.io/kube-openapi/cmd/openapi-gen)",
             "--v 1",
             "--logtostderr",
-            "--go-header-file $$ORIG_WD/$(location //" + vendor_prefix + "hack/boilerplate:boilerplate.go.txt)",
+            "--go-header-file $$GO_GENRULE_EXECROOT/$(location //" + vendor_prefix + "hack/boilerplate:boilerplate.go.txt)",
             "--output-file-base zz_generated.openapi",
             "--output-package " + go_prefix + "pkg/generated/openapi",
             "--report-filename tmp_api_violations.report",
             "--input-dirs " + ",".join([go_prefix + target for target in openapi_targets] + [go_prefix + "vendor/" + target for target in vendor_targets]),
-            "&& cp $$GOPATH/src/" + go_prefix + "pkg/generated/openapi/zz_generated.openapi.go $$ORIG_WD/$(location :zz_generated.openapi.go)",
+            "&& cp $$GOPATH/src/" + go_prefix + "pkg/generated/openapi/zz_generated.openapi.go $$GO_GENRULE_EXECROOT/$(location :zz_generated.openapi.go)",
             "&& rm tmp_api_violations.report",
         ]),
         go_deps = deps,