waylandtouch: Don't export interface structs

These are explicitly written in C code rather than generated at build
time, so they weren't affected by changing how we invoke
wayland-scanner.

Signed-off-by: Simon McVittie <smcv@collabora.com>

src/video/wayland/SDL_waylandtouch.c

@@ -160,7 +160,7 @@ static const struct wl_message qt_touch_extension_events[] = {
     { "configure", "u", qt_touch_extension_types + 0 },
 };
 
-WL_EXPORT const struct wl_interface qt_touch_extension_interface = {
+const struct wl_interface qt_touch_extension_interface = {
     "qt_touch_extension", 1,
     1, qt_touch_extension_requests,
     2, qt_touch_extension_events,
@@ -183,7 +183,7 @@ static const struct wl_message qt_windowmanager_events[] = {
     { "quit", "", qt_windowmanager_types + 0 },
 };
 
-WL_EXPORT const struct wl_interface qt_windowmanager_interface = {
+const struct wl_interface qt_windowmanager_interface = {
     "qt_windowmanager", 1,
     1, qt_windowmanager_requests,
     2, qt_windowmanager_events,
@@ -214,7 +214,7 @@ static const struct wl_message qt_surface_extension_requests[] = {
     { "get_extended_surface", "no", qt_surface_extension_types + 2 },
 };
 
-WL_EXPORT const struct wl_interface qt_surface_extension_interface = {
+const struct wl_interface qt_surface_extension_interface = {
     "qt_surface_extension", 1,
     1, qt_surface_extension_requests,
     0, NULL,
@@ -232,7 +232,7 @@ static const struct wl_message qt_extended_surface_events[] = {
     { "close", "", qt_surface_extension_types + 0 },
 };
 
-WL_EXPORT const struct wl_interface qt_extended_surface_interface = {
+const struct wl_interface qt_extended_surface_interface = {
     "qt_extended_surface", 1,
     3, qt_extended_surface_requests,
     3, qt_extended_surface_events,