these functions where undocumented and unused. especially
tprivfree() was buggy missing a unlock() call. theres not
much point in supporting these functions as theres
threaddata() and procdata().
threadint() is called to interrupt channel operation or a system call.
the kernel provides a new "interrupt" procctl message to interrupt a
process commited to or being in a blocking syscall, which is similar,
but not the same. the main difference is that "interrupt" condition
is not cleared before the process actually attempts to block. also
can be cleared with "nointerrupt" ctl message. see proc(3)
chaninit() does not initialize Chan.qentry and Chan.nentry
and there is no way to get rid of such a channel. nobody is
using it, so removing the function to avoid confusion.
the namespace might be shared by other processes. instead, we
create a anonymous pipe with pipe() and use devdup to open one
end close-on-exec. this is shorter and avoids the race condition.
do not touch Execargs after writing the error message as the
process might be gone after the write. this was to manually
close the fd which isnt neccesary as the kernel will do it
for us on the following exit.
we do not need to wait for fork/execed program to finish when
not collecting waitmsg. this reduces the number of rio
processes hanging arround for each window shell just waiting
for it to terminate and then dumping the waitmsg.
