pack.cmd: introduce fMakeClean

Sometimes [make clean] cleans documents. And it takes too a long time
when building those documents. To avoid this, use fMakeClean flag.

Or, fMakeClean is needed to rebuild the executables without
configuring.

    modified:   pack.cmd
pack.cmd: remove [patches] dir when creating a source zip manually

    modified:   pack.cmd
pack.cmd: refactorize with findRm

    modified:   pack.cmd
pack.cmd: introduce fInstall

autoconf and automake do distribute sources only.

    modified:   pack.cmd
pack.cmd: add gmake.cmd to a source zip if exists

    modified:   pack.cmd
pack.cmd: add readme.txt to a package zip if exists

    modified:   pack.cmd
pack.cmd: mark start/end of configuration block

    modified:   pack.cmd
pack.cmd: simplify with sDestDir

    modified:   pack.cmd
pack.cmd: introduce sConfigureOpts for configure options

    modified:   pack.cmd