osdep: remove use of socket_error() from all code

Now that QEMU wraps the Win32 sockets methods to automatically
set errno upon failure, there is no reason for callers to use
the socket_error() method. They can rely on accessing errno
even on Win32. Remove all use of socket_error() from general
code, leaving it as a static method in oslib-win32.c only.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

util/qemu-coroutine-io.c

@@ -35,18 +35,16 @@ qemu_co_sendv_recvv(int sockfd, struct iovec *iov, unsigned iov_cnt,
 {
     size_t done = 0;
     ssize_t ret;
-    int err;
     while (done < bytes) {
         ret = iov_send_recv(sockfd, iov, iov_cnt,
                             offset + done, bytes - done, do_send);
         if (ret > 0) {
             done += ret;
         } else if (ret < 0) {
-            err = socket_error();
-            if (err == EAGAIN || err == EWOULDBLOCK) {
+            if (errno == EAGAIN || errno == EWOULDBLOCK) {
                 qemu_coroutine_yield();
             } else if (done == 0) {
-                return -err;
+                return -errno;
             } else {
                 break;
             }