Stable vector implementation

Stable vectors will be used in the lisp runtime to implement actual
vectors, instead of using the disgusting lvec trick.  This way we at
least can get attributes about the vector through one pointer hop.

alisp.h

@@ -46,6 +46,18 @@ typedef struct
 
 sv_t sv_copy(sv_t);
 
+/// Good ol' Dynamic Arrays
+typedef struct Vector
+{
+  u64 size, capacity;
+  void *data;
+} vec_t;
+
+#define VEC_MULT 2
+void vec_free(vec_t *);
+void vec_ensure_free(vec_t *, u64);
+void vec_append(vec_t *, void *, u64);
+void vec_clone(vec_t *, vec_t *);
 
 /// Inlined Dynamic arrays
 typedef struct InlineVector