; struct Allocator {
;     alloc: (U32) -> ptr
;     realloc: (ptr, U32) -> ptr
;     free: (ptr) -> ()
; }
;

; Creates a hashset for the specified allocator, hash function and equality function
; Arguments:
; r1 - The pointer to the allocator
; r2 - The hash function
; r3 - The equality function
; r4 - The hash function context
; r5 - The equality function context
; Result:
; r1 - The pointer to the hashset structure
; Info:
; The hash function should follow the stdlib calling convention
; The hash function receives one argument (the value of the item) and should return an integer which remains the same for the lifetime of the value.
; The equality function should follow the stdlib calling convention
; The equality function receives two arguments (the value of the two items) and should return either a zero (when the items are not equal) or any other value (if they are equal).
pub new_hashset: