Rework symbol visibility for easier maintenance

Save in a few special cases, _X_EXPORT should not be used in C source
files. Instead, it should be used in headers, and the proper C source
include that header. Some special cases are symbols that need to be
shared between modules, but not expected to be used by external drivers,
and symbols that are accessible via LoaderSymbol/dlopen.

  This patch also adds conditionally some new sdk header files, depending
on extensions enabled. These files were added to match pattern for
other extensions/modules, that is, have the headers "deciding" symbol
visibility in the sdk. These headers are:
o Xext/panoramiXsrv.h, Xext/panoramiX.h
o fbpict.h (unconditionally)
o vidmodeproc.h
o mioverlay.h (unconditionally, used only by xaa)
o xfixes.h (unconditionally, symbols required by dri2)

  LoaderSymbol and similar functions now don't have different prototypes,
in loaderProcs.h and xf86Module.h, so that both headers can be included,
without the need of defining IN_LOADER.

  xf86NewInputDevice() device prototype readded to xf86Xinput.h, but
not exported (and with a comment about it).

dix/getevents.c

@@ -73,10 +73,10 @@
  * DDX. The DDX is expected to call GetEventList() and then pass the list into
  * Get{Pointer|Keyboard}Events.
  */
-_X_EXPORT EventListPtr InputEventList = NULL;
-_X_EXPORT int InputEventListLen = 0;
+EventListPtr InputEventList = NULL;
+int InputEventListLen = 0;
 
-_X_EXPORT int
+int
 GetEventList(EventListPtr* list)
 {
     *list = InputEventList;
@@ -86,7 +86,7 @@ GetEventList(EventListPtr* list)
 /**
  * Pick some arbitrary size for Xi motion history.
  */
-_X_EXPORT int
+int
 GetMotionHistorySize(void)
 {
     return MOTION_HISTORY_SIZE;
@@ -117,7 +117,7 @@ key_autorepeats(DeviceIntPtr pDev, int key_code)
               (1 << (key_code & 7)));
 }
 
-_X_EXPORT void
+void
 CreateClassesChangedEvent(EventList* event,
                           DeviceIntPtr master,
                           DeviceIntPtr slave)
@@ -232,7 +232,7 @@ updateSlaveDeviceCoords(DeviceIntPtr master, DeviceIntPtr pDev)
 /**
  * Allocate the motion history buffer.
  */
-_X_EXPORT void
+void
 AllocateMotionHistory(DeviceIntPtr pDev)
 {
     int size;
@@ -268,7 +268,7 @@ AllocateMotionHistory(DeviceIntPtr pDev)
  *
  * If core is set, we only generate x/y, in INT16, scaled to screen coords.
  */
-_X_EXPORT int
+int
 GetMotionHistory(DeviceIntPtr pDev, xTimecoord **buff, unsigned long start,
                  unsigned long stop, ScreenPtr pScreen, BOOL core)
 {
@@ -475,7 +475,7 @@ updateMotionHistory(DeviceIntPtr pDev, CARD32 ms, int first_valuator,
  *
  * This MUST be absolutely constant, from init until exit.
  */
-_X_EXPORT int
+int
 GetMaximumEventsNum(void) {
     /* One base event -- device, plus valuator events.
      *  Multiply by two if we're doing non-XKB key repeats. */
@@ -783,7 +783,7 @@ countValuatorEvents(int num_valuators)
  * Convenience wrapper around GetKeyboardValuatorEvents, that takes no
  * valuators.
  */
-_X_EXPORT int
+int
 GetKeyboardEvents(EventList *events, DeviceIntPtr pDev, int type, int key_code) {
     return GetKeyboardValuatorEvents(events, pDev, type, key_code, 0, 0, NULL);
 }
@@ -809,7 +809,7 @@ GetKeyboardEvents(EventList *events, DeviceIntPtr pDev, int type, int key_code)
  * key press will trigger a matching KeyRelease, as well as the
  * KeyPresses.
  */
-_X_EXPORT int
+int
 GetKeyboardValuatorEvents(EventList *events, DeviceIntPtr pDev, int type,
                           int key_code, int first_valuator,
                           int num_valuators, int *valuators) {
@@ -906,7 +906,7 @@ GetKeyboardValuatorEvents(EventList *events, DeviceIntPtr pDev, int type,
  *
  * @param num_events Number of elements in list.
  */
-_X_EXPORT EventListPtr
+EventListPtr
 InitEventList(int num_events)
 {
     EventListPtr events;
@@ -937,7 +937,7 @@ InitEventList(int num_events)
 /**
  * Allocs min_size memory for each event in the list.
  */
-_X_EXPORT void
+void
 SetMinimumEventSize(EventListPtr list, int num_events, int min_size)
 {
     if (!list)
@@ -964,7 +964,7 @@ SetMinimumEventSize(EventListPtr list, int num_events, int min_size)
  * @param list The list to be freed.
  * @param num_events Number of elements in list.
  */
-_X_EXPORT void
+void
 FreeEventList(EventListPtr list, int num_events)
 {
     if (!list)
@@ -993,7 +993,7 @@ FreeEventList(EventListPtr list, int num_events)
  *
  * master->last.valuators[x] for x > 2 is undefined.
  */
-_X_EXPORT int
+int
 GetPointerEvents(EventList *events, DeviceIntPtr pDev, int type, int buttons,
                  int flags, int first_valuator, int num_valuators,
                  int *valuators) {
@@ -1076,7 +1076,7 @@ GetPointerEvents(EventList *events, DeviceIntPtr pDev, int type, int buttons,
  * The DDX is responsible for allocating the event structure in the first
  * place via GetMaximumEventsNum(), and for freeing it.
  */
-_X_EXPORT int
+int
 GetProximityEvents(EventList *events, DeviceIntPtr pDev, int type,
                    int first_valuator, int num_valuators, int *valuators)
 {
@@ -1128,7 +1128,7 @@ GetProximityEvents(EventList *events, DeviceIntPtr pDev, int type,
  * Used in cursor functions, e.g. when cursor confinement changes, and we need
  * to shift the pointer to get it inside the new bounds.
  */
-_X_EXPORT void
+void
 PostSyntheticMotion(DeviceIntPtr pDev,
                     int x,
                     int y,