Trying to compile with --with-debug fails

See https://github.com/zfsrogue/zfs-crypto/issues/17. 

These are some smaller fixes I managed to fix on my own, but the big one I don't know how to fix:

```
/bin/sh ../../libtool --tag=CC --silent  --mode=compile gcc -DHAVE_CONFIG_H -include ../../zfs_config.h -I../../include -I../../lib/libspl/include  -D_GNU_SOURCE -D__EXTENSIONS__ -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE -DTEXT_DOMAIN=\"zfs-linux-user\"  -Wall -Wstrict-prototypes -fno-strict-aliasing  -DDEBUG -Werror -fstack-check  -g -O2 -MT zio.lo -MD -MP -MF .deps/zio.Tpo -c -o zio.lo `test -f '../../module/zfs/zio.c' || echo './'`../../module/zfs/zio.c
../../module/zfs/zio.c: In function 'zio_decrypt':
../../module/zfs/zio.c:425: error: 'SPA_VERSION_CRYPTO' undeclared (first use in this function)
../../module/zfs/zio.c:425: error: (Each undeclared identifier is reported only once
../../module/zfs/zio.c:425: error: for each function it appears in.)
../../module/zfs/zio.c: In function 'zio_read_bp_init':
../../module/zfs/zio.c:1120: error: 'SPA_VERSION_CRYPTO' undeclared (first use in this function)
../../module/zfs/zio.c: In function 'zio_write_bp_init':
../../module/zfs/zio.c:1319: error: 'SPA_VERSION_CRYPTO' undeclared (first use in this function)
cc1: warnings being treated as errors
../../module/zfs/zio.c: In function 'zio_gang_tree_issue':
../../module/zfs/zio.c:1984: error: suggest parentheses around && within ||
make[3]: *** [zio.lo] Error 1
```