Export IsX11/IsWayland symbols needed by wxMediaCtrl library

include/wx/gtk/private/backend.h

@@ -8,7 +8,7 @@
 #ifdef __WXGTK3__
 namespace wxGTKImpl
 {
-    bool IsWayland(void* instance);
-    bool IsX11(void* instance);
+    WXDLLIMPEXP_CORE bool IsWayland(void* instance);
+    WXDLLIMPEXP_CORE bool IsX11(void* instance);
 }
 #endif

src/gtk/window.cpp

@@ -405,6 +405,7 @@ static bool IsBackend(void* instance, const char* string)
     return strncmp(string, name, strlen(string)) == 0;
 }
 
+WXDLLIMPEXP_CORE
 bool wxGTKImpl::IsWayland(void* instance)
 {
     static wxByte is = 2;
@@ -413,6 +414,7 @@ bool wxGTKImpl::IsWayland(void* instance)
     return bool(is);
 }
 
+WXDLLIMPEXP_CORE
 bool wxGTKImpl::IsX11(void* instance)
 {
     static wxByte is = 2;