Pull in bug fixes from upstream

Fix compile error with Bit_IsSet for Dqn_OS_Exec*

Add capturing of stdout/stderr output in exec API

Import latest revision of dqn lib from CSIGHT

Add dqn_cgen, reorganise files into standalone/external dirs

Add date to unix time, fix buggy array and arena prototype

Implement error sink on posix layer

Add new ErrorSink API to collate error from API calls

Add new ErrorSink API to collate error from API calls

Add more array helper functions, add U64 to I64 saturate cast

Fix compilation for emscripten backend

Import latest changes from CSIGHT project

dqn: Upgrade lib to latest version from TELY

dqn: Fix DQN_ASAN_POISON 0 breaking arenas, improve profiler API

dqn: Add more container types

dqn: Document the stack trace API

dqn: Update Windows header replacement

dqn: Implement stack trace for windows

dqn: Start mocking up stack trace lib

dqn: Only poison commit pages to speed up poison of large arenas

dqn: Simplify Hex->U64 and also remove UB right shift

dqn: Put ASAN poisoning behind macros to allow vetting

dqn: Add ASAN poisoning

dqn: Namespace tests

dqn: Move printing above debug

dqn: Minor header block comments

dqn: Re-enable clang build flags