build: specify a compiler target for tensorflow-swift-apis on macOS

Because the rest of the components have a deployment target of 10.13 explicitly, pass the same triple for the tensorflow-swift-apis build.

Author: compnerd

utils/swift_build_support/swift_build_support/products/tensorflow.py

@@ -71,15 +71,16 @@ def build(self, host_target):
                 '-D', 'CMAKE_MAKE_PROGRAM={}'.format(self.toolchain.ninja),
                 '-D', 'CMAKE_Swift_COMPILER={}'.format(swiftc),
                 # SWIFT_ENABLE_TENSORFLOW
+                '-DCMAKE_Swift_COMPILER_TARGET=x86_64-apple-macosx10.13' if host_target.startswith('macosx') else '',
                 '-D', 'USE_BUNDLED_CTENSORFLOW=YES',
-                # SWIFT_ENABLE_TENSORFLOW END
                 '-D', 'TensorFlow_INCLUDE_DIR={}'.format(tensorflow_source_dir),
                 '-D', 'TensorFlow_LIBRARY={}'.format(
                     os.path.join(tensorflow_source_dir, 'bazel-bin', 'tensorflow',
                                  lib_name)),
                 '-D', 'CMAKE_Swift_FLAGS={}'.format('-L{}'.format(
                     os.path.join(tensorflow_source_dir, 'bazel-bin', 'tensorflow'))
                 ),
+                # SWIFT_ENABLE_TENSORFLOW END
                 '-B', self.build_dir,
                 '-S', self.source_dir,
             ])