prior to this, building with iptables-1.8.9 failed with
> make[2]: Entering directory '/tmp/nix-shell.okX50g/tmp.O3HX8QruLZ/source/src/usr/iptables'
> gcc -Wall -pedantic -std=gnu11 -O2 -I../.. -I/nix/store/h6saqb0001ps7mwi1c40m90f53af1hpj-iptables-1.8.9-dev/include -D_INIT=libxt_JOOL_SIIT_init -fPIC -c -o libxt_JOOL_SIIT.o libxt_JOOL_SIIT.c;
> gcc -shared -fPIC -o libxt_JOOL_SIIT.so libxt_JOOL_SIIT.o;
> /nix/store/f4qnwzv6y0nq8lix33jr5ykkyybs6fxf-binutils-2.40/bin/ld: libxt_JOOL_SIIT.o: in function `_init':
> libxt_JOOL_SIIT.c:(.text+0x150): multiple definition of `_init'; /nix/store/1n2l5law9g3b77hcfyp50vrhhssbrj5g-glibc-2.37-8/lib/crti.o:(.init+0x0): first defined here
> collect2: error: ld returned 1 exit status
> make[2]: *** [Makefile:37: libxt_JOOL_SIIT.so] Error 1
This adds the upstream fix from 490ddb0933
20761c31d0