Simplify extending the buffer
Simplify extending the buffer

Most of the callers know how much the buffer needs extending, so don't
ask them for the total size: new _ul_buffer_reserve_size replaces
_ul_buffer_ensure_size, and the fast path is now inlined.

Signed-off-by: Miloslav Trmač <9c008e38982a5397deb855345fb164f0558459ae@redhat.com>
Signed-off-by: Gergely Nagy <6780fac3b38619ac20422286e4110a70dbba2203@balabit.hu>

deirf/libumberlog