The new std.process is ready for review

[jerro]

> Of course, we have a problem if some other platform allows 
> ulong.max open files...

You can increase (on Linux) maximal number of open files by 
adding something like

your_username                hard    nofile          65536

to /etc/security/limits.conf and using ulimit. You can increase 
it up to /proc/sys/fs/file-max (which is 394062 by default on my 
machine but can also be increased) that way.

I don't know what the maximal valid value of 
/proc/sys/fs/file-max is, but it can
not be more than int.max, since file descriptors are ints.