diff --git a/library/include/modules/MapCache.h b/library/include/modules/MapCache.h
index 73a91d972..70ba0a858 100644
--- a/library/include/modules/MapCache.h
+++ b/library/include/modules/MapCache.h
@@ -55,7 +55,7 @@ class Block;
 
 struct BiomeInfo {
     // Determined by the 4-bit index in the designation bitfield
-    static const unsigned MAX_LAYERS = 16;
+    static constexpr unsigned MAX_LAYERS = 16;
 
     df::coord2d pos;
     int default_soil, default_stone, lava_stone;
diff --git a/library/modules/MapCache.cpp b/library/modules/MapCache.cpp
index d5c2e6c81..85df6156f 100644
--- a/library/modules/MapCache.cpp
+++ b/library/modules/MapCache.cpp
@@ -79,10 +79,6 @@ using df::global::world;
 
 extern bool GetLocalFeature(t_feature &feature, df::coord2d rgn_pos, int32_t index);
 
-#ifdef LINUX_BUILD
-const unsigned MapExtras::BiomeInfo::MAX_LAYERS;
-#endif
-
 const BiomeInfo MapCache::biome_stub = {
     df::coord2d(),
     -1, -1, -1, -1,