Make compilation of tor_memdup_nulterm() with dmalloc

  o Minor bugfixes (dmalloc):

    - Fix compilation with dmalloc. Fixes bug 11605; bugfix on 0.2.4.10-alpha.

/** As tor_memdup(), but add an extra 0 byte at the end of the resulting

 * memory. */

void *

tor_memdup_nulterm(const void *mem, size_t len DMALLOC_PARAMS)

tor_memdup_nulterm_(const void *mem, size_t len DMALLOC_PARAMS)

{

  char *dup;

  tor_assert(len < SIZE_T_CEILING+1);