diff --git a/options/ansi/include/locale.h b/options/ansi/include/locale.h
index 7851152476..82838927b0 100644
--- a/options/ansi/include/locale.h
+++ b/options/ansi/include/locale.h
@@ -13,6 +13,7 @@
 #define LC_NUMERIC 5
 #define LC_TIME 6
 #define LC_MESSAGES 7
+#define LC_MEASUREMENT 11
 
 #define LC_GLOBAL_LOCALE ((locale_t) -1L)