basic port could be small.
* Add a `-E` option to `rpctrace` to specify environment variables: https://savannah.gnu.org/task/index.php?9331
* Use libz and libbz2 in exec. See `hurd/exec/unzip.c` etc., they should be replaced by mere calls to libraries, https://savannah.gnu.org/task/index.php?6990
+* Add `/proc/$pid/maps`. `vminfo` already has this kind of information, it's a matter of making procfs do the same. https://savannah.gnu.org/bugs/?32770
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