5 1 new backport x11 fs rework (#1485)

* Use XRandR 1.2 to set fullscreen resolution for single output

Squash of roothorick's PR #497
(also includes Kyzentun's CMake changes from PR #716)

* Cherry-pick json c++1x stuff (b9e3d7174e)

* Cherry-pick c++11 support from 5bba5c0038 and 9f8b045309

* rework Linux (X11) fullscreen, improve display-related Graphics Options

Implement option to select between monitors for exclusive fullscreen mode
on X11 (using XRandR 1.2), or use a fullscreen borderless window.

Reimplement resolution/refresh rate/display mode-related option rows
using Lua, update choices dynamically so only known-good groupings of
resolution/refresh rate/aspect ratio can be selected.

Minimally update Windows/MacOS LowLevelWindow implementations to support
changes made for Linux side. Fullscreen Borderless Window/multi monitor
support from X11 not implemented for those in this commit.

* allow forcibly disabling xinerama use on Linux

When libXinerama is available, SM tries to use it to find the proper
monitor indexes to use to set _NET_WM_FULLSCREEN_MONITORS (on borderless
fullscreen). xfwm4 seems to assume that monitors are numbered in increasing
order from left to right (rather than using the Xinerama-assigned numbers),
so _NET_WM_FULLSCREEN_MONITORS misbehaves on Xfce.

This commit bypasses use of libXinerama, and instead forces SM to induce fullscreen
on the desired monitor in the backup, hacky way: remove all window hints, move window
to desired monitor, then add _NET_WM_STATE_FULLSCREEN hint. This works on
mutter and Xfce.

* Remove multiple warnings on redundant define.

This used to be hard-coded due to pthread related items, but now it's dynamically determined.

* fix _fallback menu behavior for unrecognized aspect ratios

* Fix error recreating existing FS texture

* Bump deployment target to 10.7 to use libc++ on XCode 8

* Add explicit casts to please clang

* Update changelog

src/archutils/Unix/X11Helper.h

@@ -4,6 +4,8 @@
 
 #include <X11/Xlib.h>		// Window
 #include <X11/Xutil.h>
+#include <DisplaySpec.h>
+
 namespace X11Helper
 {
 	// All functions in here that return a bool return true on success, and
@@ -25,6 +27,12 @@ namespace X11Helper
 	// (Re)create the Window win.
 	bool MakeWindow( Window &win, int screenNum, int depth, Visual *visual,
 			 int width, int height, bool overrideRedirect );
+
+	void SetWMState( const Window &root, const Window &win, const long action, const Atom atom );
+
+#ifdef HAVE_XINERAMA
+	bool SetWMFullscreenMonitors( const DisplaySpec &target );
+#endif
 };
 
 #endif