Imports of pack command

PathSynopsis
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
ioPackage io provides basic interfaces to I/O primitives.
logPackage log implements a simple logging package.
osPackage os provides a platform-independent interface to operating system functionality.
path/filepathPackage filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths.
strconvPackage strconv implements conversions to and from string representations of basic data types.
stringsPackage strings implements simple functions to manipulate UTF-8 encoded strings.
timePackage time provides functionality for measuring and displaying time.
unicode/utf8Package utf8 implements functions and constants to support text encoded in UTF-8.