VM Resident Executables update:
Kernel Part:
* decrement the exec_res_id counter in exec_sys_unregister, otherwise
we will have an incorrect count of currently resident executables.
* add a structure called 'xresident' which stores enough information
about resident executables, so that we can export it to userland
via sysctl; the structure resides in sys/resident.h.
* add a sysctl node, called 'vm.resident' which enumerates though
exec_res_list, i.e., the queue which stores information about the
executables that are currently resident
* move the exec_res_list queue initialization and a MALLOC_DEFINE
near the top of the file, right after the include files; and also
initialize the exec_res_id counter to '0'.
NOTE! The 'vm.resident' sysctl node is only available to root!
Userland Part:
* add a '-l' option to resident(8), so that it displays the list
of executables that are currently memory-resident.
* update the program usage string so that it is in par with the
functionality offered by the program.
* update the manual page.
Requested-by: many...
Discussed-with: Matthew Dillon <dillon@backplane.com>