[patch 2/2+rfc+doc] Install gcore by default (+new man page)

[Eli Zaretskii]

> Date: Sun, 7 Apr 2013 20:54:43 +0200
> From: Jan Kratochvil <jan.kratochvil@redhat.com>
> 
> +Produced file is equivalent to a kernel produced core file as if the process
> +crashed (and also it had to have @command{ulimit -c} enabled appropriately).

Suggest to reword in parentheses:

  (and if @kbd{ulimit -c} were used to set up an appropriate core dump
  limit)

Note: @kbd, not @command, as the latter is for command names, not for
command lines.

> +Contrary to it after @command{gcore} the program remains running without any
> +change.

"Unlike after a crash, after @command{gcore} the program ..."

The documentation part is OK with these changes.

Thanks.