Don't try to use -mod=... when go.mod doesn't exist

Also don't pass a blank argument to `go` when using an old version.

Author: smowton

extractor/cli/go-autobuilder/go-autobuilder.go

@@ -508,8 +508,13 @@ func main() {
 	}
 
 	var cmd *exec.Cmd
-	log.Printf("Running extractor command '%s %s ./...' from directory '%s'.\n", extractor, modMode, cwd)
-	cmd = exec.Command(extractor, modMode.String(), "./...")
+	if depMode == GoGetWithModules && modMode.String() != "" {
+		log.Printf("Running extractor command '%s %s ./...' from directory '%s'.\n", extractor, modMode, cwd)
+		cmd = exec.Command(extractor, modMode.String(), "./...")
+	} else {
+		log.Printf("Running extractor command '%s ./...' from directory '%s'.\n", extractor, cwd)
+		cmd = exec.Command(extractor, "./...")
+	}
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	err = cmd.Run()