diff --git a/src/newgrf_spritegroup.h b/src/newgrf_spritegroup.h
--- a/src/newgrf_spritegroup.h
+++ b/src/newgrf_spritegroup.h
@@ -26,7 +26,7 @@
  * @pre i < 0x110
  * @return the value of the register
  */
-static inline uint32_t GetRegister(uint i)
+inline uint32_t GetRegister(uint i)
 {
 	extern TemporaryStorageArray<int32_t, 0x110> _temp_store;
 	return _temp_store.GetValue(i);