Move definition of socket_t to util.hh

It's used in multiple places so dedicated place for its definition
is necessary

src/conn.cc

@@ -91,7 +91,7 @@ rtp_format_t kvz_rtp::connection::get_payload() const
     return rtp_payload_;
 }
 
-kvz_rtp::socket_t kvz_rtp::connection::get_raw_socket()
+socket_t kvz_rtp::connection::get_raw_socket()
 {
     return socket_.get_raw_socket();
 }

src/socket.cc

@@ -18,6 +18,7 @@ using namespace mingw;
 
 #include "debug.hh"
 #include "socket.hh"
+#include "util.hh"
 
 kvz_rtp::socket::socket():
     recv_handler_(nullptr),
@@ -117,7 +118,7 @@ void kvz_rtp::socket::set_sockaddr(sockaddr_in addr)
     addr_ = addr;
 }
 
-kvz_rtp::socket_t& kvz_rtp::socket::get_raw_socket()
+socket_t& kvz_rtp::socket::get_raw_socket()
 {
     return socket_;
 }

src/socket.hh

@@ -18,11 +18,9 @@
 namespace kvz_rtp {
 
 #ifdef _WIN32
-    typedef SOCKET socket_t;
     typedef unsigned socklen_t;
     typedef TRANSMIT_PACKETS_ELEMENT vecio_buf;
 #else
-    typedef int socket_t;
     typedef mmsghdr vecio_buf;
 #endif
 

src/util.hh

@@ -22,6 +22,12 @@
 #define PACKED_STRUCT(name) struct name
 #endif
 
+#ifdef _WIN32
+    typedef SOCKET socket_t;
+#else
+    typedef int socket_t;
+#endif
+
 const int MAX_PACKET      = 65536;
 const int MAX_PAYLOAD     = 1441;