Remove superfluous X11 library struct member.

src/x11_init.c

@@ -459,8 +459,6 @@ static void detectEWMH(void)
         getSupportedAtom(supportedAtoms, atomCount, "_NET_WM_BYPASS_COMPOSITOR");
 
     XFree(supportedAtoms);
-
-    _glfw.x11.hasEWMH = GL_TRUE;
 }
 
 // Initialize X11 display and look for supported X11 extensions

src/x11_platform.h

@@ -115,8 +115,6 @@ typedef struct _GLFWlibraryX11
     XContext        context;
     // XIM input method
     XIM             im;
-    // True if window manager supports EWMH
-    GLboolean       hasEWMH;
     // Most recent error code received by X error handler
     int             errorCode;
     // Clipboard string (while the selection is owned)

src/x11_window.c

@@ -317,15 +317,17 @@ static GLboolean createWindow(_GLFWwindow* window,
                      (XPointer) window);
     }
 
-    if (window->monitor && !_glfw.x11.hasEWMH)
+    if (window->monitor)
+    {
+        if (!_glfw.x11.NET_WM_STATE || !_glfw.x11.NET_WM_STATE_FULLSCREEN)
         {
             // This is the butcher's way of removing window decorations
-        // Setting the override-redirect attribute on a window makes the window
-        // manager ignore the window completely (ICCCM, section 4)
+            // Setting the override-redirect attribute on a window makes the
+            // window manager ignore the window completely (ICCCM, section 4)
             // The good thing is that this makes undecorated full screen windows
-        // easy to do; the bad thing is that we have to do everything manually
-        // and some things (like iconify/restore) won't work at all, as those
-        // are tasks usually performed by the window manager
+            // easy to do; the bad thing is that we have to do everything
+            // manually and some things (like iconify/restore) won't work at
+            // all, as those are tasks usually performed by the window manager
 
             XSetWindowAttributes attributes;
             attributes.override_redirect = True;
@@ -336,6 +338,7 @@ static GLboolean createWindow(_GLFWwindow* window,
 
             window->x11.overrideRedirect = GL_TRUE;
         }
+    }
 
     // Declare the WM protocols supported by GLFW
     {