diff --git a/test/unittests/unit_maybe_alloc.c b/test/unittests/unit_maybe_alloc.c
index 25b41d46..985e28f7 100644
--- a/test/unittests/unit_maybe_alloc.c
+++ b/test/unittests/unit_maybe_alloc.c
@@ -4,6 +4,14 @@
 #include <assert.h>
 #include <cmocka.h>
 
+/* Apparently not supported in very old cmocka versions */
+#ifndef assert_ptr_equal
+#define assert_ptr_equal(a, b) \
+    _assert_int_equal(cast_ptr_to_largest_integral_type(a), \
+                      cast_ptr_to_largest_integral_type(b), \
+                      __FILE__, __LINE__)
+#endif
+
 extern void mock_assert(const int result, const char* const expression,
                         const char * const file, const int line);
 #undef assert