GCFuncs and GCOps are const since 1.16.
diff --git a/unix/xserver/hw/vnc/vncHooks.cc b/unix/xserver/hw/vnc/vncHooks.cc
index 29de4c4..f75a2d4 100644
--- a/unix/xserver/hw/vnc/vncHooks.cc
+++ b/unix/xserver/hw/vnc/vncHooks.cc
@@ -89,8 +89,13 @@
 } vncHooksScreenRec, *vncHooksScreenPtr;
 
 typedef struct {
+#if XORG >= 116
     const GCFuncs *wrappedFuncs;
     const GCOps *wrappedOps;
+#else
+    GCFuncs *wrappedFuncs;
+    GCOps *wrappedOps;
+#endif
 } vncHooksGCRec, *vncHooksGCPtr;
 
 #if XORG == 15
@@ -916,7 +921,11 @@
   }
   GCPtr pGC;
   vncHooksGCPtr vncHooksGC;
+#if XORG >= 116
   const GCFuncs* oldFuncs;
+#else
+  GCFuncs* oldFuncs;
+#endif
   ScreenPtr pScreen;
 };