Merge #18524: refactor: drop boost::signals2 in validationinterface
Summary:
d6815a2313158862d448733954a73520f223deb6 refactor: drop boost::signals2 in validationinterface (Russell Yanofsky)
Pull request description:
Stop using boost::signals2 internally in validationinterface. Replace with std::list and Add/Remove/Clear/Iterate helper functions. Motivation for change is to reduce dependencies and avoid issues happening with boost versions before 1.59: https://github.com/bitcoin/bitcoin/issues/18517, https://github.com/bitcoin/bitcoin/pull/18471
ACKs for top commit:
MarcoFalke: ACK d6815a2313158862d448733954a73520f223deb6 laanwj: ACK d6815a2313158862d448733954a73520f223deb6 hebasto: re-ACK d6815a2313158862d448733954a73520f223deb6 promag: ACK d6815a2313158862d448733954a73520f223deb6.
Tree-SHA512: 4fc0f14a8446e8616cc142af6c3d36815f3254525d30348ba8e4d4bc74c249a5a8c9bc119bdd1be7ebd7abe0b784bc0c5551a3e156a766890cb2fdd891a95919
Backport of Core PR18524
Depends on D6652
Test Plan: ninja check check-functional
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Subscribers: Fabien
Differential Revision: https://reviews.bitcoinabc.org/D6653