!): Fix for Ubuntu 18.04 linking error.

mediapipe/examples/desktop/BUILD

@@ -27,6 +27,5 @@ cc_library(
         "//mediapipe/framework/port:parse_text_proto",
         "//mediapipe/framework/port:status",
         "@com_google_absl//absl/strings",
-	"//external:unwind"
     ],
 )

mediapipe/examples/desktop/media_sequence/BUILD

@@ -37,4 +37,7 @@ cc_binary(
         "//mediapipe/graphs/media_sequence:clipped_images_from_file_at_24fps_calculators",
         "//mediapipe/graphs/media_sequence:tvl1_flow_and_rgb_from_file_calculators",
     ],
+    linkopts = [
+        "-lunwind",
+    ],
 )

mediapipe/examples/desktop/object_detection/BUILD

@@ -63,6 +63,9 @@ cc_binary(
         "//mediapipe/graphs/object_detection:desktop_tensorflow_calculators",
         "@org_tensorflow//tensorflow/core:direct_session",
     ],
+    linkopts = [
+        "-lunwind",
+    ],
 )
 
 cc_binary(
@@ -71,4 +74,7 @@ cc_binary(
         "//mediapipe/examples/desktop:simple_run_graph_main",
         "//mediapipe/graphs/object_detection:desktop_tflite_calculators",
     ],
+    linkopts = [
+        "-lunwind",
+    ],
 )