Add dependency checker special case for out/build_date.txt.

	miniBootstrapDir := filepath.Join(outDir, "soong", ".minibootstrap")

	modulePathsDir := filepath.Join(outDir, ".module_paths")

	variablesFilePath := filepath.Join(outDir, "soong", "soong.variables")

	// dexpreopt.config is an input to the soong_docs action, which runs the

	// soong_build primary builder. However, this file is created from $(shell)

	// invocation at Kati parse time, so it's not an explicit output of any

	// treated as an source file.

	dexpreoptConfigFilePath := filepath.Join(outDir, "soong", "dexpreopt.config")

	// out/build_date.txt is considered a "source file"

	buildDatetimeFilePath := filepath.Join(outDir, "build_date.txt")

	danglingRules := make(map[string]bool)

	scanner := bufio.NewScanner(stdout)

			strings.HasPrefix(line, miniBootstrapDir) ||

			strings.HasPrefix(line, modulePathsDir) ||

			line == variablesFilePath ||

			line == dexpreoptConfigFilePath {

			line == dexpreoptConfigFilePath ||

			line == buildDatetimeFilePath {

			// Leaf node is in one of Soong's bootstrap directories, which do not have

			// full build rules in the primary build.ninja file.

			continue