285656 by ed:
Add an API for easily creating userspace threads in kernelspace.
This change refactors the existing create_thread() function to be more
generic. It replaces almost all of its arguments by a callback that can
be used to extract the thread ID and copy it out to the right place, but
also to perform additional initialization steps, such as setting the
trapframe. This also makes the difference between thr_new() and
thr_create() more clear in my opinion.
This function is going to be used by the CloudABI compatibility layer.
285657 by pkelsey:
Check TCP timestamp option flag so that the automatic receive buffer
scaling code does not use an uninitialized timestamp echo reply value
from the stack when timestamps are not enabled.