Use safe_strerror instead of strerror where possible

This provides threadsafety. Unfortunately, since libinproctrace.so
does not link to gnulib, we can't use it there, especially since it
still includes the gnulib headers (so it is difficult to directly
call the system strerror_r).

gdb/ChangeLog:

2019-11-26  Christian Biesinger  <cbiesinger@google.com>

	* linux-nat.c (detach_one_lwp): Call safe_strerror instead of
	strerror.
	* nto-procfs.c (nto_procfs_target::create_inferior): Likewise.
	* windows-nat.c (windows_nat_target::create_inferior): Likewise.

gdb/gdbserver/ChangeLog:

2019-11-26  Christian Biesinger  <cbiesinger@google.com>

	* debug.c (debug_set_output): Call safe_strerror instead of
	strerror.
	* linux-low.c (attach_proc_task_lwp_callback): Likewise.
	(linux_kill_one_lwp): Likewise.
	(linux_detach_one_lwp): Likewise.
	(linux_wait_for_event_filtered): Likewise.
	(store_register): Likewise.
	* lynx-low.c (lynx_attach): Likewise.
	* mem-break.c (insert_memory_breakpoint): Likewise.
	(remove_memory_breakpoint): Likewise.
	(delete_fast_tracepoint_jump): Likewise.
	(set_fast_tracepoint_jump): Likewise.
	(uninsert_fast_tracepoint_jumps_at): Likewise.
	(reinsert_fast_tracepoint_jumps_at): Likewise.
	* nto-low.c (nto_xfer_memory): Likewise.
	(nto_resume): Likewise.

Change-Id: I9e259cdcaa6e11bbcc4ee6bdc5b7127d73e11abe

gdb/linux-nat.c

@@ -1420,7 +1420,7 @@ detach_one_lwp (struct lwp_info *lp, int *signo_p)
 	  if (ret == -1)
 	    {
 	      warning (_("Couldn't reap LWP %d while detaching: %s"),
-		       lwpid, strerror (errno));
+		       lwpid, safe_strerror (errno));
 	    }
 	  else if (!WIFEXITED (status) && !WIFSIGNALED (status))
 	    {