Frees a linked list of memory blocks of structure type type.
The memory blocks must be equal-sized, allocated via g_slice_alloc() or g_slice_alloc0() and linked together by a next pointer (similar to GSList). The offset of the next field in each block is passed as third argument. Note that the exact release behaviour can be changed with the [G_DEBUG=gc-friendly]G_DEBUG environment variable, also see [G_SLICE]G_SLICE for related debugging options.
If mem_chain is NULL, this function does nothing.