Mixing code and declarations is ugly, anyways.

We could probably get away with using alloca(), but I'm not sure
how good compiler support is for that, either.  It's probably
more supported than mixed declarations and code.  Nevertheless;
we'll trigger memory checkers on exit because we don't free
the buffers; but we won't actually leak because we reuse those
buffers (just like the non-SRC code path).

git-svn-id: https://svn.musicpd.org/mpd/trunk@5397 09075e82-0dd4-0310-85a5-a0d7c8717e4f