unix: add missing function declaration
unix: fix compiler warning, #include <unistd.h>
unix: add uv_fs_read64, uv_fs_write64 and uv_fs_ftruncate64
unix: don't conditionally compile kqueue fs watcher

Always compile in the kqueue-based fs event watcher and handle it at run-time
if the kernel doesn't actually support it.

Works around build issues when -mmacosx-version-min is not set properly.

Fixes joyent/node#3075.
unix: fix udp_options test on OS X and Solaris

setsockopt(IP_TTL) will happily let you set a TTL > 255 on OS X, cap it.

-1 or 0 is a valid TTL on Linux but not portable, deny it.
Tests: don't use %zu placeholder in printf statements

It's not supported by msvcrt.
test: disable fs_event_close_in_callback on kqueue-based systems
Whitespace
Add UV_EIO error code
Disable ipc_send_recv_pipe test on Windows

It's not supported yet
unix: run pending shutdown cb when stream is closed
Windows: validate UDP socket options

Makes test-udp-options pass on Windows.
Windows: make uv_uptime() more robust
Windows: make uv_dlopen() look in the DLL path to resolve recursive dependencies
Fix spawn_and_kill_with_std test
unix: map `EROFS` to `UV_EROFS`
windows: map ERROR_WRITE_PROTECT to UV_EROFS
test: fix race conditions in test-async
test: fix a race condition in 'async' test
windows: a closing async watcher should not call it's callback