Build advice request: Ubuntu 20.04.1 LTS

[simonwhittle]

Hello,

I receive the following errors when trying to run "make" on Ubuntu 20.04.1 LTS:

root@simon:/opt/ts3init# make
make -C src;
make[1]: Entering directory '/opt/ts3init/src'
make -C /lib/modules/5.4.0-58-generic/build M=$PWD;
make[2]: Entering directory '/usr/src/linux-headers-5.4.0-58-generic'
  AR      /opt/ts3init/src/built-in.a
  CC [M]  /opt/ts3init/src/ts3init_module.o
  CC [M]  /opt/ts3init/src/ts3init_match.o
/opt/ts3init/src/ts3init_match.c: In function ‘ts3init_get_cookie_mt’:
/opt/ts3init/src/ts3init_match.c:201:9: warning: ISO C90 forbids variable length array ‘payload_buf’ [-Wvla]
  201 |         __u8 *payload, payload_buf[ts3init_payload_sizes[COMMAND_GET_COOKIE]];
      |         ^~~~
/opt/ts3init/src/ts3init_match.c: In function ‘ts3init_get_puzzle_mt’:
/opt/ts3init/src/ts3init_match.c:267:9: warning: ISO C90 forbids variable length array ‘payload_buf’ [-Wvla]
  267 |         __u8 *payload, payload_buf[ts3init_payload_sizes[COMMAND_GET_PUZZLE]];
      |         ^~~~
  CC [M]  /opt/ts3init/src/ts3init_cookie.o
/opt/ts3init/src/ts3init_cookie.c: In function ‘check_update_seed_cache’:
/opt/ts3init/src/ts3init_cookie.c:61:14: error: ‘struct shash_desc’ has no member named ‘flags’
   61 |         shash->flags = 0;
      |              ^~
make[3]: *** [scripts/Makefile.build:275: /opt/ts3init/src/ts3init_cookie.o] Error 1
make[2]: *** [Makefile:1757: /opt/ts3init/src] Error 2
make[2]: Leaving directory '/usr/src/linux-headers-5.4.0-58-generic'
make[1]: *** [Makefile:10: all] Error 2
make[1]: Leaving directory '/opt/ts3init/src'
make: *** [Makefile:2: all] Error 2
root@simon:/opt/ts3init# 

After Googling, I can get around the "ISO C90 forbids variable length array" issue by adding -std=c99 as a switch on the gcc lines in Makefile.xtables. However, I don't know how to fix error: ‘struct shash_desc’ has no member named ‘flags’ error.

Any advice appreciated.

Thanks in advance,

Simon