usage: ./pkgtool.sh [-a nt32|nt64] [-b debug|release] [-i|-m <dname>|-r|-s|-t]
                    [<variable name>=<variable override>[ ..]]            name

        -a nt32|nt64      Selects 32-bit or 64-bit architecture; defaults to nt64.
        -b debug|release  Selects debug or release build kind; defaults to debug.
        -i                List package variables and dependencies of single named package.
        -m <dname>        Setup package archives mirror in <dname>
        -r                List reverse dependencies of single named package.
        -s                Enter interactive package build shell environment for single
                          named package; requires a package dump file. If the package
                          has not been built yet or built successfully, it will be rebuilt
                          at build steps up until, by default, the `build' build step and
                          forcibly aborted and dumped prior to enterting the shell.
        -t                Produce tarball of package build root directory and build log
                          file for the purpose of distribution given build failure.

        <variable name>=<variable override>[ ..]
                          Override build variable.