How can I use git malloc wrapper in my code?

I want to use git malloc and realloc shells in my code for OOM conditions (out of memory). Here is his code:

void *xmalloc(size_t size)
{
      void *ret = malloc(size);
      if (!ret && !size)
              ret = malloc(1);
      if (!ret) {
              release_pack_memory(size, -1);
              ret = malloc(size);
              if (!ret && !size)
                      ret = malloc(1);
              if (!ret)
                      die("Out of memory, malloc failed");
      }
#ifdef XMALLOC_POISON
      memset(ret, 0xA5, size);
#endif
      return ret;
}

but the release_pack_memory function is located in the sha1_file.c header file, and this function has links to functions in other header files in git and I did not want to make so much effort to isolate this function from git codebase. I'm currently looking for an alternative function for the release_pack_memory function, or you can recommend me another alternative. I will be grateful for any help