qspawn: shorten lifetime of environ and opts args

We don't need to hold onto the subprocess environ and
redirects/options for popen_rd after spawning the child process.

I do not expect this to fix problem of leaking unlinked regular
file descriptors (which I still can't reproduce), and it
definitely does not fix the problem of leaking pipe descriptors
(which I also can't reproduce).

This will save an FD sooner on non-public-inbox-httpd servers
which give a non-FD $env->{'psgi.input'}, however

Regardless, it's good to free up memory resources in our own
process ASAP we're done using them.

0 files changed, 0 insertions, 0 deletions