Compile errors with clang on FreeBSD

[aseprano]

There are several compile issues using clang on my freebsd machine:

1. missing <array> inclusion:

In file included from process.cpp:9:
In file included from ./includes.h:39:
./../include/pipe.h:25:24: error: implicit instantiation of undefined template 'std::__1::array<int, 2>'
std::array<int, 2> _fds;

so I added it to src/includes.h

2. watchers/write.cpp:35 calls ev_io_init() which generates the following: use of overloaded operator '|' is ambiguous (with operand types '<anonymous enum at /usr/local/include/ev.h:211:1>' and
   '<anonymous enum at /usr/local/include/ev.h:211:1>')
   This ambiguity candidate are the enum containing the EV_* values in ev.h and the uint128_t class, so I forced an int cast in src/watchers/write.cpp:

ev_io_init(&_watcher, onActive, fd, (int)EV_WRITE);

3. same as 2 but applies to watchers/read.cpp

4. the file include/tcp/socket.h requires <sys/uio.h> for calling ::writev(_fd, iov, iovcnt) at line 286