[PATCH v4 0/5] Implement the ability to start inferiors with a shell on gdbserver

[Sergio Durigan Junior <sergiodj@redhat.com>]

Hi again,

This is the fourth version of this patch series.  You can look at the
last version sent here:

  <https://sourceware.org/ml/gdb-patches/2017-02/msg00173.html>

This version now has 5 patches instead of 6 because the first patch,
which shared gdb/environ.[ch] between GDB and gdbserver, got accepted
and pushed upstream.

The changes in this version were almost entirely made to address
Pedro's reviews (thanks!).  Here's the bulk of what changed from v3:

- We now check if the necessary headers for some terminal.h features
  are present on common/common.m4.

- Reorganized the job_control part; moved it to the correct patch (2/5
  instead of 1/5).

- Return the proper value (0) on create_tty_session.

- Reformatted the comments on gdbserver/terminal.c.

- Renamed the file to "common/job-control.c" instead of
  "common/common-inflow.c".

- Call set_executing after calling fork_inferior, which makes it
  unnecessary to expand its prototype and accept more arguments.

- Removed the "struct ui" hacks on gdbserver; replace them by some new
  functions that take care of everything from the GDB side.

- Fixed use of invalid C++ for "startup_with_shell" variable.

- Still declaring "inferior_ptid" on gdbserver/inferiors.c, but added
  a comment explaining why.

- Expanded the comment on {linux,lynx}_update_process and
  update_thread_lwp.

- Constified second argument of fork_inferior.

- Improved a few error messages.

- Improved some C++ range loops.

- Constified a few things and improved comments.

- Removed erroneous call to post_fork_inferior on Windows code.

- Improved text on NEWS file.

- Improved help text for
  "--startup-with-shell"/"--no-startup-with-shell" parameters on
  gdbserver.

- Moved code to set startup-with-shell packet to the "create_inferior"
  function on extended remote code.

- Fixed a bunch of testcase nits.


If you go to the v3 version of the patch, you can see the cover letter
as well.

This has been tested on BuildBot, and no regressions were found.

Thanks,