Add support for kernel 5.1

[ydahhrk]

15:26:14 **** Build of configuration Debug for project Jool ****
make KERNEL_DIR=/media/ydahhrk/Thicc/linux/instances/v5.1/ all 
make -C siit
make[1]: Entering directory '/home/ydahhrk/git/Jool/src/mod/siit'
make -C /media/ydahhrk/Thicc/linux/instances/v5.1/ M=$PWD JOOL_FLAGS=""
make[2]: Entering directory '/media/ydahhrk/Thicc/linux/instances/v5.1'
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../../common/common-global.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../../common/siit/xlat.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../../common/netlink/config.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/rfc6145/4to6.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/rfc6145/6to4.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/rfc6145/common.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/rfc6145/core.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/kernel_hook_netfilter.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/kernel_hook_iptables.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/address.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/atomic_config.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/common-global.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/types.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/str_utils.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/packet.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/stats.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/icmp_wrapper.o
  CC [M]  /home/ydahhrk/git/Jool/src/mod/siit/../common/rtrie.o
/home/ydahhrk/git/Jool/src/mod/siit/../common/rtrie.c: In function ‘add_full_collision’:
/home/ydahhrk/git/Jool/src/mod/siit/../common/rtrie.c:346:2: error: implicit declaration of function ‘synchronize_rcu_bh’; did you mean ‘synchronize_rcu’? [-Werror=implicit-function-declaration]
  synchronize_rcu_bh();
  ^~~~~~~~~~~~~~~~~~
  synchronize_rcu
cc1: some warnings being treated as errors
scripts/Makefile.build:275: recipe for target '/home/ydahhrk/git/Jool/src/mod/siit/../common/rtrie.o' failed
make[3]: *** [/home/ydahhrk/git/Jool/src/mod/siit/../common/rtrie.o] Error 1
Makefile:1571: recipe for target '_module_/home/ydahhrk/git/Jool/src/mod/siit' failed
make[2]: *** [_module_/home/ydahhrk/git/Jool/src/mod/siit] Error 2
make[2]: Leaving directory '/media/ydahhrk/Thicc/linux/instances/v5.1'
make[1]: *** [all] Error 2
Makefile:5: recipe for target 'all' failed
make: *** [siit] Error 2
make[1]: Leaving directory '/home/ydahhrk/git/Jool/src/mod/siit'
Makefile:8: recipe for target 'siit' failed

15:26:23 Build Failed. 9 errors, 0 warnings. (took 8s.439ms)

...

[stefanbrudny]

...and this would not have happened if kernel janitors would have been doing their job, as discussed in #273 and #140 :-)

+1 for having jool in vanilla in any form, using module or an virtual interface etc.

Having these kind of problems in 2019 looks really awkward and reminds me compiling slack dependencies in 1999... Amiga was still around then...

Sorry I don't have a skill to fix that, btw.

[ydahhrk]

Sorry about the damage :/

But, it should be fixed now. In the master branch, at least.

[ydahhrk]

Forgot to mention: Tested in kernel 5.1.1-050101-generic.