Summary

This PR fixes compiler warnings reported by modern C++ compilers (GCC 11+, Clang 15+):

Net module

• PollSet.cpp: Added (void) casts to suppress -Wunused-result warnings for read() and write() calls where return values are intentionally ignored (as documented in comments)
• RemoteSyslogListener.cpp: Fixed -Wdeprecated-enum-enum-conversion by casting enum values to int before arithmetic operations between Facility and Severity enums
• WebSocket.cpp: Fixed -Wdeprecated-enum-enum-conversion by casting FrameFlags and FrameOpcodes enum values to int before bitwise OR operation

Zip module

• ZipArchiveInfo.cpp, ZipDataInfo.cpp, ZipFileInfo.cpp, ZipLocalFileHeader.cpp, ZipUtil.cpp: Fixed -Wdeprecated-anon-enum-enum-conversion by casting anonymous enum values to std::size_t or std::streamsize when performing arithmetic with ZipCommon::HEADER_SIZE

Foundation module

• RWLockTest.cpp: Modernized to use std::atomic<int> (C++11) instead of deprecated volatile int with complex #ifdef __cpp_lib_atomic_ref fallback. This eliminates -Wdeprecated-volatile warnings while maintaining thread-safe semantics

CI

• Added macos-clang-cmake-warnings job to detect compiler warnings in future builds

Warning Types Fixed