- Use pid_t type instead of just int.

- Put arguments for print_syscall_ret() function in proper order.
  Bug was introduced in r192025.

- Remove unused variables.
- Fix warnings about comparing signed and unsigned ints.

- Style(9) cleanup.

- Remove unused variables.
- Remove redundant return after err(3) call.

- Fix detaching under some circumstances.

  When truss is detaching from very active process it is possible to
  hang on waitpid(2) in restore_proc() forever, because
  ptrace(PT_SYSCALL) must be called before detaching, to allow the
  debugging process to continue execution.  Also when truss called with
  '-c' argument, it does not print anything after detach, because it
  immediately exits from restore_proc().

  To fix these two problems make detaching deferred, but then it is
  impossible to detach from a process which does not do any system call.
  To fix this issue use sigaction(2) instead of signal(3) to disable
  SA_RESTART flag for waitpid(2) that makes it non-restartable.  Remove
  global variable child_pid, because now detaching is handled in context
  where child's pid is known.

- Make truss thread-aware.

reset props for svn keywords

Sync with FreeBSD 9 stable

sync with freebsd 7.0