- Add platform_compat.h with Windows implementations of:
* gettimeofday() using GetSystemTimeAsFileTime
* poll() using select()
* pipe() using _pipe()
* fcntl() using ioctlsocket for O_NONBLOCK
* pollfd structure and POLL* constants
* strcasecmp/strncasecmp macros
- Update debug_config.c and u_async.c/h to use platform_compat.h
- Remove POSIX-specific headers (arpa/inet.h, sys/time.h, etc.)
- All 22 tests pass on Linux
- Fixes build errors on Windows MSYS2
Evgeny