buflib: Add buflib_context_relocate().

This function relocates a buflib back buffer, updating pointers in struct
buflib_context. It does not move any data by itself.

The intended use-case is buflib-on-buflib, where a buflib back buffer is
allocated with buflib and attempted to be moved. The move_callback() can call
this and return BUFLIB_CB_OK on success. No move_callback() is called for the
subordinate buflib buffer, therefore it must not contain non-movable
allocations. The caller is generally responsible moving the data and all its
implications.

Change-Id: I869219f9cff786a172c9e917a5f34470073892e6

0 files changed, 0 insertions, 0 deletions