[PATCHES 9-12/12] line_buffer: more wrappers around stdio functions

This might be the last batch of line_buffer patches for the moment[1].
It introduces wrappers around strbuf_fread, fgetc, fdopen, and tmpfile
so the line_buffer lib can do what those functions do.

The motivation in the background is delta application.  We need:

 - binary-safe input, since svn (like most version control systems)
   gets used to store binary files from time to time.
 - character-oriented input (fgetc) as a basic convenience, needed in
   particular for reading variable-length integers in svndiff blocks.
 - input from file descriptors, to read information requested from
   fast-import (in particular, delta preimages).
 - temporary files, to store the result of delta application and
   retrieve its length so svn-fe can write

	data <length>
	... delta application result ...

   to fast-import.

The ideas behind the third and fourth patches (patches 11 and 12) are
from David Barr's earlier work in the same direction.  Patches are
based against

  [PATCH 8/8] t0081 (line-buffer): add buffering tests

so we can reuse some of the testing infrastructure.  They are numbered
accordingly for easy application.

Each patch introduces new API.  I would be happy if you can find an
infelicity or two so we can fix the functions now before people get
used to them.

Jonathan Nieder (4):
  vcs-svn: add binary-safe read function
  vcs-svn: allow character-oriented input
  vcs-svn: allow input from file descriptor
  vcs-svn: teach line_buffer about temporary files

 t/t0081-line-buffer.sh  |   27 +++++++++++++++++++++++++++
 test-line-buffer.c      |   21 ++++++++++++++++++---
 vcs-svn/line_buffer.c   |   43 +++++++++++++++++++++++++++++++++++++++++++
 vcs-svn/line_buffer.h   |   10 +++++++++-
 vcs-svn/line_buffer.txt |   31 +++++++++++++++++++++++++++----
 5 files changed, 124 insertions(+), 8 deletions(-)

[1] There's another patch to use 64-bit offsets but the API changes
are more obvious.