Milter-greylist

Hello.

Tring to compile milter-greylist in older linux, which however is ipv6
compatible, and runs on 2.4 kernel, but getting error:

gcc -g -O2 -Wall -Ino/include -Ino/include -D_XOPEN_SOURCE=500
-D_BSD_SOURCE   -c -o pending.o pending.c
pending.c: In function `ip_match':
pending.c:423: structure has no member named `sin6_scope_id'
pending.c:424: structure has no member named `sin6_scope_id'
pending.c:424: structure has no member named `sin6_scope_id'
pending.c: In function `ip_equal':
pending.c:457: structure has no member named `sin6_scope_id'
pending.c:458: structure has no member named `sin6_scope_id'
pending.c:458: structure has no member named `sin6_scope_id'
make: *** [pending.o] Error 1

Seems some ipv6 incompatible error, how to fix it?