libcutils: add multi-buffer socket send.

Unix and Windows both have functions to write multiple buffers to a
socket with a single call but they have very different signatures. This
CL creates some cross-platform functions to be able to perform these
operations in a uniform way, which will be required for upcoming
fastboot functionality.

This CL also fixes some inconsistent spacing in the touched files.

Bug: http://b/26558551
Change-Id: I8f14d52d3a1de1f3b464267666d6cd3b54263238
diff --git a/libcutils/sockets_windows.c b/libcutils/sockets_windows.c
index 1bf2933..8153688 100644
--- a/libcutils/sockets_windows.c
+++ b/libcutils/sockets_windows.c
@@ -58,3 +58,22 @@
     return setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (char*)&timeout_ms,
                       sizeof(timeout_ms));
 }
+
+cutils_socket_buffer_t make_cutils_socket_buffer(void* data, size_t length) {
+    cutils_socket_buffer_t buffer;
+    buffer.buf = data;
+    buffer.len = length;
+    return buffer;
+}
+
+ssize_t socket_send_buffers(cutils_socket_t sock,
+                            cutils_socket_buffer_t* buffers,
+                            size_t num_buffers) {
+    DWORD bytes_sent = 0;
+
+    if (WSASend(sock, buffers, num_buffers, &bytes_sent, 0, NULL, NULL) !=
+            SOCKET_ERROR) {
+        return bytes_sent;
+    }
+    return -1;
+}