diff --git a/src/viewport.cpp b/src/viewport.cpp
index 4ac7f5f11d..e243967236 100644
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -86,6 +86,7 @@
 #include "bridge_map.h"
 
 #include <map>
+#include <math.h>
 
 #include "table/strings.h"
 #include "table/string_colours.h"
diff --git a/src/viewport_type.h b/src/viewport_type.h
index 3455a86290..90b14599b4 100644
--- a/src/viewport_type.h
+++ b/src/viewport_type.h
@@ -15,7 +15,6 @@
 #include "zoom_type.h"
 #include "strings_type.h"
 #include "table/strings.h"
-#include "math.h"
 
 class LinkGraphOverlay;