Fix undefined symbol errors on building otelcorecol for Plan 9

.chloggen/otelcol-plan9build.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: loggingexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fix undefined symbol errors on building otelcorecol for Plan 9
+
+# One or more tracking issues or pull requests related to the change
+issues: [6924]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

exporter/loggingexporter/known_sync_error.go

@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build !windows
-// +build !windows
+//go:build linux || darwin
+// +build linux darwin
 
 package loggingexporter // import "go.opentelemetry.io/collector/exporter/loggingexporter"
 

exporter/loggingexporter/known_sync_error_plan9.go

@@ -0,0 +1,24 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build plan9
+// +build plan9
+
+package loggingexporter // import "go.opentelemetry.io/collector/exporter/loggingexporter"
+
+// knownSyncError returns true if the given error is one of the known
+// non-actionable errors returned by Sync on Plan 9.
+func knownSyncError(err error) bool {
+	return false
+}