Add missing #include <stdio.h>.

Author: petervdonovan

C/Savina/src/micro/Big.lf

@@ -41,6 +41,7 @@ target C{
 import BenchmarkRunner from "../BenchmarkRunner.lf";
 
 preamble {=
+    #include <stdio.h>
     #include "PseudoRandom.h"
 =}