[PATCH 8/8] membuf: Support a flag for being full

[Simon Glass]

At present the membuf implementation wastes a slot in the fifo so it can
detect the difference between a full and an empty buffer.

Add the option of supporting a boolean flag, if desired. For now it is
off.

The code-size penalty is non-zero, but the space penalty is small and
could be reduced on 64-bit machines by using a u32 offset for head and
tail.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 include/membuf.h  |  6 +++++
 lib/membuf.c      | 63 ++++++++++++++++++++++++++++++++++++++---------
 test/lib/membuf.c | 11 ++++++---
 3 files changed, 65 insertions(+), 15 deletions(-)

Applied to sjg/master, thanks!