void replace_prefix (char **pname, const char *samp, size_t slen,
const char *repl, size_t rlen);
char *tar_savedir (const char *name, int must_exist);
void replace_prefix (char **pname, const char *samp, size_t slen,
const char *repl, size_t rlen);
char *tar_savedir (const char *name, int must_exist);