diff --git a/cmd/multicall.h b/cmd/multicall.h
index bd7cf7d..647e0ba 100644
--- a/cmd/multicall.h
+++ b/cmd/multicall.h
@@ -20,8 +20,6 @@
 
 #include "libifupdown/libifupdown.h"
 
-#define ARRAY_SIZE(x)   (sizeof(x) / sizeof(*x))
-
 struct if_applet;
 
 struct if_option {
diff --git a/libifupdown/libifupdown.h b/libifupdown/libifupdown.h
index 87cc5fd..33da802 100644
--- a/libifupdown/libifupdown.h
+++ b/libifupdown/libifupdown.h
@@ -28,4 +28,8 @@
 #include "libifupdown/lifecycle.h"
 #include "libifupdown/tokenize.h"
 
+#ifndef ARRAY_SIZE
+# define ARRAY_SIZE(x)   (sizeof(x) / sizeof(*x))
+#endif
+
 #endif