Fixes the following warning:

    mpq.c: In function ‘libmpq__block_open_offset’:
    mpq.c:698:128: warning: taking address of packed member of ‘struct <anonymous>’ may result in an unaligned pointer value [-Waddress-of-packed-member]
      698 | pq__decrypt_key((uint8_t *)mpq_archive->mpq_file[file_number]->packed_offset, packed_size, mpq_archive->block_size, &mpq_archive->mpq_file[file_number]->seed) < 0) {
          |                                                                                                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes mbroemme#6

    explode.c: In function ‘libmpq__do_decompress_pkzip’:
    explode.c:542:73: warning: taking address of packed member of ‘struct <anonymous>’ may result in an unaligned pointer value [-Waddress-of-packed-member]
     542 |  mpq_pkzip->in_bytes   = mpq_pkzip->read_buf((char *)mpq_pkzip->in_buf, &mpq_pkzip->in_pos, mpq_pkzip->param);