diff --git i/src/cbare.c w/src/cbare.c
index 208639f..a3081fb 100644
--- i/src/cbare.c
+++ w/src/cbare.c
@@ -4,7 +4,9 @@
 #include "cbare.h"
 #include "utf8.h"
 
+#ifndef UNUSED
 #define UNUSED(x) (void)(x)
+#endif
 
 enum {
 	U8SZ = 1,
diff --git i/test/baretest.c w/test/baretest.c
index 1561f4c..9df740f 100644
--- i/test/baretest.c
+++ w/test/baretest.c
@@ -10,7 +10,9 @@
 #include "alloc.h"
 #include "die.h"
 
+#ifndef UNUSED
 #define UNUSED(x) (void)(x)
+#endif
 
 #define ARRLEN(a) sizeof(a)/sizeof(a[0])