Undef X_DISPLAY_MISSING

As of f815f9840d several years ago nothing sets
this #define anywhere anymore.

res/config.h.in

@@ -160,8 +160,5 @@
 /* Define to 1 if your <sys/time.h> declares `struct tm`. */
 #cmakedefine TM_IN_SYS_TIME ${TM_IN_SYS_TIME}
 
-/* Define to 1 if the X Window System is missing or not being used. */
-#cmakedefine X_DISPLAY_MISSING ${X_DISPLAY_MISSING}
-
 /* Define to `unsigned int` if <sys/types.h> does not define. */
 #cmakedefine size_t ${size_t}

src/lib/platform/IXWindowsImpl.h

@@ -3,9 +3,6 @@
 
 #include "config.h"
 
-#if X_DISPLAY_MISSING
-#	error X11 is required to build barrier
-#else
 #include <X11/X.h>
 #include <X11/Xutil.h>
 #define XK_MISCELLANY
@@ -36,7 +33,6 @@
 #ifdef HAVE_XI2
 #	include <X11/extensions/XInput2.h>
 #endif
-#endif
 
 class IXWindowsImpl {
 public:

src/lib/platform/XWindowsClipboard.h

@@ -25,11 +25,7 @@
 #include "common/stdvector.h"
 #include "XWindowsImpl.h"
 
-#if X_DISPLAY_MISSING
-#    error X11 is required to build barrier
-#else
 #include <X11/Xlib.h>
-#endif
 
 class IXWindowsClipboardConverter;
 

src/lib/platform/XWindowsEventQueueBuffer.h

@@ -23,11 +23,7 @@
 #include "common/stdvector.h"
 #include "XWindowsImpl.h"
 
-#if X_DISPLAY_MISSING
-#    error X11 is required to build barrier
-#else
 #include <X11/Xlib.h>
-#endif
 
 class IEventQueue;
 

src/lib/platform/XWindowsKeyState.cpp

@@ -24,9 +24,6 @@
 
 #include <cstddef>
 #include <algorithm>
-#if X_DISPLAY_MISSING
-#    error X11 is required to build barrier
-#else
 #include <X11/X.h>
 #include <X11/Xutil.h>
 #define XK_MISCELLANY
@@ -35,7 +32,6 @@
 #if HAVE_XKB_EXTENSION
 #    include <X11/XKBlib.h>
 #endif
-#endif
 
 static const size_t ModifiersFromXDefaultSize = 32;
 

src/lib/platform/XWindowsKeyState.h

@@ -23,9 +23,6 @@
 #include "common/stdvector.h"
 #include "XWindowsImpl.h"
 
-#if X_DISPLAY_MISSING
-#    error X11 is required to build barrier
-#else
 #include <X11/Xlib.h>
 #if HAVE_X11_EXTENSIONS_XTEST_H
 #    include <X11/extensions/XTest.h>
@@ -35,7 +32,6 @@
 #if HAVE_XKB_EXTENSION
 #    include <X11/extensions/XKBstr.h>
 #endif
-#endif
 
 class IEventQueue;
 

src/lib/platform/XWindowsScreen.h

@@ -24,11 +24,7 @@
 #include "common/stdvector.h"
 #include "XWindowsImpl.h"
 
-#if X_DISPLAY_MISSING
-#    error X11 is required to build barrier
-#else
 #include <X11/Xlib.h>
-#endif
 
 class XWindowsClipboard;
 class XWindowsKeyState;

src/lib/platform/XWindowsScreenSaver.h

@@ -23,11 +23,7 @@
 #include "common/stdmap.h"
 #include "XWindowsImpl.h"
 
-#if X_DISPLAY_MISSING
-#    error X11 is required to build barrier
-#else
 #include <X11/Xlib.h>
-#endif
 
 class Event;
 class EventQueueTimer;

src/lib/platform/XWindowsUtil.h

@@ -22,11 +22,7 @@
 #include "common/stdmap.h"
 #include "common/stdvector.h"
 
-#if X_DISPLAY_MISSING
-#    error X11 is required to build barrier
-#else
 #include <X11/Xlib.h>
-#endif
 
 #include <string>