Fix compilation with gcc 4.7
Fix compilation with gcc 4.7

An explicit conversion between uint8_t * and ac_ptr was needed to
correctly match the overloaded function load_array

tiagofalcao/ArchC,lianaduenha/ArchC,tiagofalcao/ArchC,tiagofalcao/ArchC,tiagofalcao/ArchC,tiagofalcao/ArchC,tiagofalcao/ArchC,lianaduenha/ArchC,lianaduenha/ArchC,lianaduenha/ArchC,tiagofalcao/ArchC