Enforce exclusive release config component directories

	directories := []string{}

	valueDirectories := []string{}

	// These path prefixes are exclusive for a release config.

	// "A release config shall exist in at most one of these."

	// If we find a benefit to generalizing this, we can do so at that time.

	exclusiveDirPrefixes := []string{

		"build/release",

		"vendor/google_shared/build/release",

	}

	var exclusiveDir string

	for idx, confDir := range configs.configDirs {

		if _, ok := myDirsMap[idx]; ok {

			directories = append(directories, confDir)

		}

		if _, ok := myValueDirsMap[idx]; ok {

			for _, dir := range exclusiveDirPrefixes {

				if strings.HasPrefix(confDir, dir) {

					if exclusiveDir != "" && !strings.HasPrefix(exclusiveDir, dir) {

						return fmt.Errorf("%s is declared in both %s and %s",

							config.Name, exclusiveDir, confDir)

					}

					exclusiveDir = confDir

				}

			}

			valueDirectories = append(valueDirectories, confDir)

		}

	}