ash: rewrite waitpid_child() to improve performance

After the previous commit there was still a slight disparity
between shell performance with and without background jobs.
Reduce this disparity by the following changes:

- Remove the pidlist array.  The PID of the exiting process can be
  obtained from its handle.

- Save the proclist array between calls.  It will always grow to
  support the required number of PIDs.

- Combine the loops to compute the required size of proclist and
  to fill it.  This saves a few bytes with no measurable impact
  on performance.

Saves 8 bytes in a 32-bit build, adds 32 in 64-bit.

(GitHub issue #434)

0 files changed, 0 insertions, 0 deletions