diff --git a/libc/upstream-netbsd/android/include/netbsd-compat.h b/libc/upstream-netbsd/android/include/netbsd-compat.h
index 5dd086e..a625f06 100644
--- a/libc/upstream-netbsd/android/include/netbsd-compat.h
+++ b/libc/upstream-netbsd/android/include/netbsd-compat.h
@@ -43,6 +43,8 @@
 #include <stddef.h>
 int reallocarr(void*, size_t, size_t);
 
+#define __arraycount(a) (sizeof(a) / sizeof(a[0]))
+
 /* Use appropriate shell depending on process's executable. */
 __LIBC_HIDDEN__ extern const char* __bionic_get_shell_path();
 #define _PATH_BSHELL __bionic_get_shell_path()