Fix TensorFlow stdlib module compilation.

Sources/TensorFlow/Context.swift

@@ -18,7 +18,9 @@ import Darwin
 import Glibc
 #endif
 
+#if !COMPILING_TENSORFLOW_STDLIB_MODULE
 import Tensor
+#endif
 
 /// A value that indicates the phase of using a machine learning model.
 public enum LearningPhase {

Sources/TensorFlow/Exports.swift

@@ -12,5 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#if !COMPILING_TENSORFLOW_STDLIB_MODULE
 // Re-export all public symbols in the Tensor library.
 @_exported import Tensor
+#endif

Sources/TensorFlow/Initializers.swift

@@ -12,7 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#if !COMPILING_TENSORFLOW_STDLIB_MODULE
 import Tensor
+#endif
 
 public extension Tensor {
     /// Creates a tensor with the specified shape and a single, repeated scalar value.

Sources/TensorFlow/Layers/Initialization.swift

@@ -12,7 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#if !COMPILING_TENSORFLOW_STDLIB_MODULE
 import Tensor
+#endif
 
 public typealias ParameterInitializer<Scalar: TensorFlowScalar> = (TensorShape) -> Tensor<Scalar>
 

Sources/TensorFlow/Layers/Recurrent.swift

@@ -12,7 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#if !COMPILING_TENSORFLOW_STDLIB_MODULE
 import Tensor
+#endif
 
 /// An input to a recurrent neural network.
 public struct RNNCellInput<Input: Differentiable, State: Differentiable>: Differentiable {