The .in.in file was added to the repo in 8bdfa6a4e56f. Then Gary added the .in file to POTFILES.in in 1d98555... but I think it should actually be the .in.in file, right?
/*
* pidgin
*
* Pidgin is the legal property of its developers, whose names are too numerous
* to list here. Please refer to the COPYRIGHT file distributed with this
* source distribution.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA
*
*/
#include"internal.h"
#include"gtkidle.h"
#ifdef HAVE_IOKIT
#include<CoreFoundation/CoreFoundation.h>
#include<IOKit/IOKitLib.h>
#else
# ifdef USE_SCREENSAVER
# ifdef _WIN32
#include"gtkwin32dep.h"
# else
/* We're on X11 and not MacOS X with IOKit. */
#include<X11/Xlib.h>
#include<X11/Xutil.h>
#include<X11/extensions/scrnsaver.h>
#include<gdk/gdkx.h>
# endif /* !_WIN32 */
# endif /* USE_SCREENSAVER */
#endif /* !HAVE_IOKIT */
#include"idle.h"
/*
* pidgin_get_time_idle:
*
* Get the number of seconds the user has been idle. In Unix-world
* this is based on the X Windows usage. In MS Windows this is
* based on keyboard/mouse usage information obtained from the OS.
* In MacOS X, this is based on keyboard/mouse usage information
* obtained from the OS, if configure detected IOKit. Otherwise,
* MacOS X is handled as a case of X Windows.
*
* In Debian bug #271639, jwz says:
*
* Purple should simply ask xscreensaver how long the user has been idle: