Add missing permit_filesystem check to readlink/fstatat

Also prevent negative fds to pass std-pipe check

Add rounding mode support to FCVT_W_SD

This solves a bug where std::floor() didn't work in a C++ environment

Fix missing zero-termination in guest string larger than SSO

Merge pull request #307 from libriscv/fb2

FreeBSD fixes

bintr: Disable faulty forward-jumping call optimization

It caused a stack overflow on Windows with TCC-JIT

Merge pull request #290 from libriscv/fix_fcvt

Fix conversion issue with FCVT.S.W and FCVT.S.WU

Link against libtcc normally

Fix DecoderCache needs to be zeroed with binary translation

Long-running applications continously re-use memory, and when
binary translation is loadable it pre-populates the decoder cache
with entries. A dirty decoder cache can potentially lead to the
decoder finding wrong bintr entries, which can lead to rare jumps
that don't lead to any productive execution. It may even loop forever
since the binary translation will not find an entry for the current
PC, return back, and then the wrong entry jumps right back.

Let's just zero the whole decoder cache to begin with. I chose to
always zero regardless of binary translation settings, just in case.

Bump version to v1.9

Update README