The struct growarray (typedef garray_T) is used for growing arrays.
Growing arrays grow only and and are then deleted all at once.
Growing arrays are accessed using an index.
Functions that deal with growing arrays start with ga_…() and are defined in misc2.c.
typedef struct growarray
{
int ga_len; // current number of items used
int ga_maxlen; // maximum number of items possible
int ga_itemsize; // sizeof(item)
int ga_growsize; // number of items to grow each time
void *ga_data; // pointer to the first item
} garray_T;