This release brings significant bugfixes and performance improvements.

• Allow SIGSYS handlers in Fil-C. I previously disallowed them thinking that they are risky; they aren't.
• Make dladdr work.
• Don't crash with an assert if unsafe-to-handle sighandlers were previously SIG_IGN.
• Make Fil-C stack dumps show the shared object that each function comes from.
• Fix musl support for open and close actions in posix_spawn.
• Make all obstack-using programs in /opt/fil and pizlix use one capability per allocation.
• Significantly improve the compiler's handling of unions: (a) fix multiple cases where unions such as those used in std::optional<> previously resulted in capabilities being dropped and (b) improve performance of union codegen (~4% net speed-up on PizBench).
• Make pthread API for requesting stack bounds work. Also add zstack_pointer intrinsic that can be used by code wanting to do its own stack checks.
• Add environment variables to dump heap graphs and stack traces in response to signals.
• Make truncate work.
• Make waitid work.
• Fix ioctl in static binaries.
• Teach libcurl how to find certs on all of the Linux distributions.
• Make it possible to run the /opt/fil setup.sh script unattended.

Guide to the available files:

• filc-0.678-linux-x86_64.tar.xz is the traditional, self-contained "pizfix" distribution. It only includes the compiler, doesn't require root, and is based on the musl libc. This is recommended for quickly trying out Fil-C.
• optfil-0.678-linux-x86_64.tar.xz is the /opt/fil distribution. It includes many useful programs like OpenSSH, sudo, tmux, and git. It's based on glibc 2.40, and requires root permissions. This is recommended for giving Fil-C deeper scrutiny.