Add @com_google_absl//absl/strings:cord (#1308)

Fix read/STDIN_FILENO

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

Author: yongtang

tensorflow_io/core/kernels/text_kernels.cc

@@ -16,10 +16,11 @@ limitations under the License.
 #include "tensorflow/core/framework/op_kernel.h"
 #include "tensorflow/core/lib/io/buffered_inputstream.h"
 #include "tensorflow_io/core/kernels/io_stream.h"
-
 #if defined(_MSC_VER)
 #include <io.h>
 #define STDIN_FILENO _fileno(stdin)
+#else
+#include <unistd.h>
 #endif
 
 namespace tensorflow {

tensorflow_io/core/kernels/video_kernels.h

@@ -23,6 +23,7 @@ limitations under the License.
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <unistd.h>
 
 static int xioctl(int fh, int request, void* arg) {
   int r;

third_party/toolchains/tf/BUILD.tpl

@@ -8,6 +8,7 @@ cc_library(
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/container:inlined_vector",
         "@com_google_absl//absl/strings",
+        "@com_google_absl//absl/strings:cord",
         "@com_google_absl//absl/types:optional",
         "@com_google_absl//absl/types:span",
     ],