dns/dnsmasq-devel: Update to new upstream release candidate #2.

Changelog (from Git):

• fc19399 2020-03-05 | Fix compiler warning. (HEAD -> master, tag: v2.81rc2, origin/master, origin/HEAD) [Simon Kelley]
• 980b14f 2020-03-05 | Compiler warning. [Simon Kelley]
• 1df73fe 2020-03-05 | Remove compiler warnings in IPv6 checksum code in dump.c [Simon Kelley]
• c125c1d 2020-03-05 | Update decline address handling in DHCPv6 for new multi-address world. [Simon Kelley]
• e39c484 2020-03-05 | Fix parameters to setsockopt() for TCP_FASTOPEN. [Matthias Andree]
• 977a5a2 2020-03-02 | Merge i18n messages. [Simon Kelley]
• 02df000 2020-03-02 | Trivial formatting fix. [Simon Kelley]

Drop previous patches, and add two new ones,
one to fix pkgconfig for lua,
one to fix the bitfield flag testing in rfc3315.c/DHCPv6 decline handling.