diff --git a/libcutils/ashmem-host.c b/libcutils/ashmem-host.c
index cfb5d66..7873964 100644
--- a/libcutils/ashmem-host.c
+++ b/libcutils/ashmem-host.c
@@ -32,7 +32,9 @@
 
 #include <cutils/ashmem.h>
 
+#ifndef __unused
 #define __unused __attribute__((__unused__))
+#endif
 
 int ashmem_create_region(const char *ignored __unused, size_t size)
 {