curl: Update to 7.84.0

This is a feature and bugfix update. Release notes are available at:
https://curl.se/changes.html#7_84_0



Backport a patch fixing a compile issue where sched.h was not included
on certain platforms.

Signed-off-by: Robert Joslyn <robert.joslyn@redrectangle.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>