adb: fix subprocess exit handling, oom adjust fixes, extra debugging.

* Add support for correctly handling subprocess termination in shell service  (b/3400254 b/3482112 b/2249397)
 - have a waitpid() track the subprocess, then notify the fdevent via a socket
 - force an eof on the pty master in fdevent's new subproc handler.
 - modify fdevent to force-read the pty after an exit.
* Migrate the "shell:blabla" handling to "#if !ADB_HOST" sections, where it
 belongs.
* Fix the race around OOM adjusting.
  - Do it in the child before exec() instead of the in the parent as the
   child could already have started or not (no /proc/pid/... yet).
* Allow for multi-threaded D() invocations to not clobber each other.
  - Allow locks across object files.
  - Add lock within D()
  - Make sure sysdesp init (mutex init also) is called early.
* Add some missing close(fd) calls
  - Match similar existing practices near dup2()
* Add extra D() invocations related to FD handling.
* Warn about using debugging as stderr/stdout is used for protocol.
* Fix some errno handling and make D() correctly handle it.
* Add new adb trace_mask: services.
* Make fdevent_loop's handle BADFDs more gracefully (could occur some subproc closed its pts explicitely).
* Remove obsolete commandline args reported in help. (b/3509092)


Change-Id: I928287fdf4f1a86777e22ce105f9581685f46e35
18 files changed