[lldb][docs] Add strace example to Debugging doc

This has been very useful lately debugging remote
connections. In some cases it's probably better
than our own logging.

Author: DavidSpickett

lldb/docs/resources/debugging.rst

@@ -213,11 +213,26 @@ child processes.
 The same goes for ``printf``. If it's called in a child process you won't see
 the output.
 
-In these cases consider either interactive debugging ``lldb-server`` or
+In these cases consider interactive debugging ``lldb-server`` or
 working out a more specific command such that it does not have to spawn a
 subprocess. For example if you start with ``platform`` mode, work out what
 ``gdbserver`` mode process it spawns and run that command instead.
 
+Another option if you have ``strace`` available is to trace the whole process
+tree and inspect the logs after the session has ended. ::
+
+  $ strace -ff -o log -p $(pidof lldb-server)
+
+This will log all syscalls made by ``lldb-server`` and processes that it forks.
+``-ff`` tells ``strace`` to trace child processes and write the results to a
+separate file for each process, named using the prefix given by ``-o``.
+
+Search the log files for specific terms to find the process you're interested
+in. For example, to find a process that acted as a ``gdbserver`` instance::
+
+  $ grep "gdbserver" log.*
+  log.<N>:execve("<...>/lldb-server", [<...> "gdbserver", <...>) = 0
+
 Remote Debugging
 ----------------