Comment 6 for bug 1863136

Unfortunately we require some more 5.6 compat fixes as 5.6-rc3 fails to build with the current 2 compat upstream fixes:

make[3]: Entering directory '/usr/src/linux-headers-5.6.0-050600rc3-generic'
  CC [M] /var/lib/dkms/zfs/0.8.3/build/module/avl/avl.o
  CC [M] /var/lib/dkms/zfs/0.8.3/build/module/icp/illumos-crypto.o
  LD [M] /var/lib/dkms/zfs/0.8.3/build/module/avl/zavl.o
  CC [M] /var/lib/dkms/zfs/0.8.3/build/module/lua/lapi.o
In file included from /var/lib/dkms/zfs/0.8.3/build/include/spl/sys/condvar.h:33,
                 from /var/lib/dkms/zfs/0.8.3/build/include/sys/zfs_context.h:38,
                 from /var/lib/dkms/zfs/0.8.3/build/include/sys/crypto/common.h:39,
                 from /var/lib/dkms/zfs/0.8.3/build/module/icp/illumos-crypto.c:35:
/var/lib/dkms/zfs/0.8.3/build/include/spl/sys/time.h:88:15: error: unknown type name ‘time_t’
   88 | static inline time_t
      | ^~~~~~
/var/lib/dkms/zfs/0.8.3/build/include/spl/sys/time.h: In function ‘gethrtime’:
/var/lib/dkms/zfs/0.8.3/build/include/spl/sys/time.h:108:18: error: storage size of ‘ts’ isn’t known
  108 | struct timespec ts;
      | ^~
/var/lib/dkms/zfs/0.8.3/build/include/spl/sys/time.h:109:2: error: implicit declaration of function ‘getrawmonotonic’ [-Werror=implicit-function-declaration]
  109 | getrawmonotonic(&ts);
      | ^~~~~~~~~~~~~~~
/var/lib/dkms/zfs/0.8.3/build/include/spl/sys/time.h:108:18: warning: unused variable ‘ts’ [-Wunused-variable]
  108 | struct timespec ts;
      | ^~
cc1: some warnings being treated as errors

I'll revisit this once the appropriate 5.6 compat fixes have landed.