This is a bugfix release.

• Makes prctl calls for installing sandboxes apply to Fil-C runtime threads as well as the calling thread.
• Harden the implementation of fork(2) against signals even in cases where the libc gets it wrong.
• Support more long double math functions in glibc.
• Improve the compiler's use of linker attributes. Results in a small improvement to code size of stripped binaries.
• Make sure that SIGSYS cannot be handled.
• Fix a super rare GC crash resulting from a race condition in libpas's medium size lookup table.

Guide to the available files:

• filc-0.677-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-0.677-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.