Consistency with numeric values

[EmielBruijntjes]

We currently use int, long and jit_type_sys_int to represent numeric values, and size_t to store string lengths. We need to check if all these types are the same, especially when you switch between jit and regular context.

[EmielBruijntjes]

We probably only need long and jit_type_sys_long when we deal with numeric values, and size_t when working with string lengths, where we have to investigate what the identical type to a size_t is in libjit.

[schoentoon]

As for libjit and the size_t typedef, a simple grep on the libjit header files revealed this to me.

/* TODO: the proper place for this is jit-def.h and it's going to depend on the platform. */
typedef unsigned int jit_size_t;

But as their TODO suggests it indeed depends on platform. Just like int, unsigned int is 32 bit with both 32 and 64 bit binaries, while sizeof(size_t) returns 8 for 64 bit binaries and 4 for 32 bit binaries. I think jit_type_sys_ulong is a better solution as it is the same size as size_t in both 32 and 64 bit binaries.