MINOR: debug: add -dA to dump an archive of all dependencies

MINOR: debug: add -dA to dump an archive of all dependencies

This adds "-dA[file]" on the command line, which dumps an archive of all
dependencies detected at runtime into the designated file in tar format.
This is equivalent to "set-dumpable libs", but instead of keeping the libs
in memory, it dumps them into a file. This may be used after a core dump,
in order to provide all necessary libraries to developers to permit them
to exploit the core. This may not be available on all operating systems.