1 files changed, 2 insertions, 0 deletions
diff --git a/pref.h b/pref.h
index 6feaa76f3..7345e4eac 100644
--- a/pref.h
+++ b/pref.h
@@ -5,6 +5,8 @@
 extern "C" {
 #endif
 
+#include "units.h"
+
 /* can't use 'bool' for the boolean values - different size in C and C++ */
 typedef struct
 {