Dictionaries of constants

[pgoodman]

Add in something like:

#define TRY_REGISTER_CONST(x) \
  if (__builtin_constant_p(x)) { \
    asm(".pushsection .data.consts; .quad %0; .popsection;" : : "I"(x));
  }

Then use TRY_REIGSTER_CONST in things like CHECK_EQ(a, b), and then find a way to load in the constants to libFuzzer/AFL for their dictionaries.