Fix missing #define if PLATFORM_C not here
diff --git a/programs/test/benchmark.c b/programs/test/benchmark.c
index 735b443..912aa7d 100644
--- a/programs/test/benchmark.c
+++ b/programs/test/benchmark.c
@@ -33,6 +33,7 @@
 #define polarssl_exit       exit
 #define polarssl_printf     printf
 #define polarssl_snprintf   snprintf
+#define polarssl_free       free
 #endif
 
 #if !defined(POLARSSL_TIMING_C)