[PATCH 0/3] the return of the strbuf

  While getting rid of ->eof in strbuf (as it was somehow tasteless). It
made me aware of the fact that fast-import.c was using a custom buffer
implementation (I think that was the fourth if not the fifth). So here
is the series that eradicates it.

  Trying to understand fast-import.c code, I happened to remark that it
was possible to avoid many reallocations, just by reusing old buffers
rather than dropping them (this was not possible in a readable way
before, but it is now, and uses the same mechanisms that was garbage
collecting buffers, to swap them instead).

  I've not enough stuff to do real-life tests of the old fast-import and
the new one, but I wouldn't be surprised that it gives a quite nice
speed improvements for tools that use long fast-import batches. If not,
well, the code is shorter and more readable, hence it's still a gain.