treewide: use inline helper for accessing first screen

Instead of everybody directly accessing the (internal) screenInfo struct,
let those consumers only interested in first screen use a little helper.

Also caching the value if it's needed several times.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

hw/xwin/winkeybd.c

@@ -35,6 +35,7 @@
 #include <xwin-config.h>
 #endif
 
+#include "dix/screenint_priv.h"
 #include "mi/mi_priv.h"
 
 #include "win.h"
@@ -256,8 +257,8 @@ winRestoreModeKeyStates(void)
 
     /* Only process events if the rootwindow is mapped. The keyboard events
      * will cause segfaults otherwise */
-    if (screenInfo.screens[0]->root &&
-        screenInfo.screens[0]->root->mapped == FALSE)
+    ScreenPtr firstScreen = dixGetFirstScreenPtr();
+    if (firstScreen->root && firstScreen->root->mapped == FALSE)
         processEvents = FALSE;
 
     /* Force to process all pending events in the mi event queue */

hw/xwin/winmsgwindow.c

@@ -26,6 +26,8 @@
 #include <xwin-config.h>
 #endif
 
+#include "dix/screenint_priv.h"
+
 #include "win.h"
 
 /*
@@ -56,7 +58,7 @@ winMsgWindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
            has set the DE_TERMINATE flag so exits the msg dispatch loop.
          */
         {
-            ScreenPtr pScreen = screenInfo.screens[0];
+            ScreenPtr pScreen = dixGetFirstScreenPtr();
 
             winScreenPriv(pScreen);
             PostMessage(pScreenPriv->hwndScreen, WM_GIVEUP, 0, 0);