fix centos5 build

internal/gobackfill/gte_1_12.go

@@ -0,0 +1,18 @@
+// Copyright 2020 New Relic Corporation. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+// Golang code for Go versions greater or equal than 1.12.
+//
+// +build go1.12
+
+package gobackfill
+
+import "os/exec"
+
+// ExitCode wrapping to backfill old Golang versions.
+// Negative values mean:
+// * -1: not exited
+// * -2: unknown
+func ExitCode(exitError *exec.ExitError) int {
+	return exitError.ExitCode()
+}

internal/gobackfill/lt_1_12.go

@@ -0,0 +1,15 @@
+// Copyright 2020 New Relic Corporation. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+// Golang code for Go versions lower than 1.12.
+//
+// +build !go1.12
+
+package gobackfill
+
+import "os/exec"
+
+// ExitCode not supported, always value -2, as -1 belong to not finished.
+func ExitCode(exitError *exec.ExitError) int {
+	return -2
+}

internal/integrations/v4/executor/executor.go

@@ -13,6 +13,7 @@ import (
 	"os/exec"
 	"sync"
 
+	"github.com/newrelic/infrastructure-agent/internal/gobackfill"
 	"github.com/newrelic/infrastructure-agent/internal/integrations/v4/constants"
 	"github.com/newrelic/infrastructure-agent/pkg/helpers"
 	"github.com/newrelic/infrastructure-agent/pkg/log"
@@ -101,7 +102,7 @@ func (r *Executor) Execute(ctx context.Context, pidChan, exitCodeCh chan<- int)
 			out.Errors <- err
 			if exitCodeCh != nil {
 				if exitError, ok := err.(*exec.ExitError); ok {
-					exitCodeCh <- exitError.ExitCode()
+					exitCodeCh <- gobackfill.ExitCode(exitError)
 				}
 			}
 		}