Merge branch 'ph/strbuf'

Merge branch 'ph/strbuf'

* ph/strbuf: (44 commits)
  Make read_patch_file work on a strbuf.
  strbuf_read_file enhancement, and use it.
  strbuf change: be sure ->buf is never ever NULL.
  double free in builtin-update-index.c
  Clean up stripspace a bit, use strbuf even more.
  Add strbuf_read_file().
  rerere: Fix use of an empty strbuf.buf
  Small cache_tree_write refactor.
  Make builtin-rerere use of strbuf nicer and more efficient.
  Add strbuf_cmp.
  strbuf_setlen(): do not barf on setting length of an empty buffer to 0
  sq_quote_argv and add_to_string rework with strbuf's.
  Full rework of quote_c_style and write_name_quoted.
  Rework unquote_c_style to work on a strbuf.
  strbuf API additions and enhancements.
  nfv?asprintf are broken without va_copy, workaround them.
  Fix the expansion pattern of the pseudo-static path buffer.
  builtin-for-each-ref.c::copy_name() - do not overstep the buffer.
  builtin-apply.c: fix a tiny leak introduced during xmemdupz() conversion.
  Use xmemdupz() in many places.
  ...