Relanding change to add config to enable S3 file system support.

Pass --config=s3 argument to Bazel to build with S3 file system support.
Change was originally rolled back due to a failure it caused in
//tensorflow/core/kernels:control_flow_ops_test on Macs which is now fixed.

PiperOrigin-RevId: 171579378
diff --git a/configure.py b/configure.py
index 9ca614f..9da49b6 100644
--- a/configure.py
+++ b/configure.py
@@ -991,6 +991,8 @@
                 'with_gcp_support', False, 'gcp')
   set_build_var(environ_cp, 'TF_NEED_HDFS', 'Hadoop File System',
                 'with_hdfs_support', False, 'hdfs')
+  set_build_var(environ_cp, 'TF_NEED_S3', 'Amazon S3 File System',
+                'with_s3_support', True, 's3')
   set_build_var(environ_cp, 'TF_ENABLE_XLA', 'XLA JIT', 'with_xla_support',
                 False, 'xla')
   set_build_var(environ_cp, 'TF_NEED_GDR', 'GDR', 'with_gdr_support',