FpDebugger (pure): Ignore SIGCHLD signal and let the debuggee handle it (Linux)

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@45884 4005530d-fff6-0310-9dd1-cebe43e6787f
FpDebugger (pure): Ignore SIGCHLD signal and let the debuggee handle it (Darwin)

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@45885 4005530d-fff6-0310-9dd1-cebe43e6787f