Tag RC3 for 1.24.0 release. Tested by bulding a set of samples (avr, moxiebox, xtensa-fsf-linux-uclibc, arm-unknown-linux-musleabi, x86_64-multilib-linux-gnu) in all docker containers. Except for Alpine, all pass. Alpine is considered experimental, it uses a different libc flavor (musl) so some build utilities (such as rpcgen in glibc) fail to compile for the build machine. Fixing that is not a release blocker.