logwrapper: switch to signal handlers for SIGCHLD

Switch to a signal handler to monitor SIGCHLD.
Also, clean up the exit path and log a warning when the
previous SIGCHLD sigaction is not default or ignore.

Change-Id: I7ef7daabee18d80e9e82fba3943cf1d03b504ae3
1 file changed
tree: 94735d86c7c62a817322bdc9a9f405dc6c63c638
  1. liblog/
  2. logcat/
  3. logwrapper/