Fix standalone_sender BUILD.gn for Mac.

Merges the source_set("standalone_sender") target with the
executable("cast_sender") target, to become a single executable target.
This fixes the cast_sender build on Mac (not sure why it was working on
Linux???).

Change-Id: Ifef996c56892079bfb692be756d3e2e6ea9ffe85
Reviewed-on: https://chromium-review.googlesource.com/c/openscreen/+/2619025
Reviewed-by: Jordan Bayles <jophba@chromium.org>
Commit-Queue: Jordan Bayles <jophba@chromium.org>
diff --git a/cast/standalone_sender/BUILD.gn b/cast/standalone_sender/BUILD.gn
index 0143163..a59d244 100644
--- a/cast/standalone_sender/BUILD.gn
+++ b/cast/standalone_sender/BUILD.gn
@@ -20,7 +20,7 @@
     }
   }
 
-  source_set("standalone_sender") {
+  executable("cast_sender") {
     deps = [
       "../../platform",
       "../../third_party/jsoncpp",
@@ -28,10 +28,11 @@
       "../common:public",
       "../common/channel/proto:channel_proto",
       "../sender:channel",
+      "../streaming:common",
       "../streaming:sender",
     ]
 
-    sources = []
+    sources = [ "main.cc" ]
     include_dirs = []
     lib_dirs = []
     libs = []
@@ -58,22 +59,11 @@
       libs += ffmpeg_libs + libopus_libs + libvpx_libs
     }
 
+    configs += [ "../common:certificate_config" ]
+
     public_configs = [
       "../../build:openscreen_include_dirs",
       ":standalone_external_libs",
     ]
   }
-
-  executable("cast_sender") {
-    sources = [ "main.cc" ]
-
-    configs += [ "../common:certificate_config" ]
-
-    deps = [
-      ":standalone_sender",
-      "../../third_party/jsoncpp",
-      "../common/channel/proto:channel_proto",
-      "../streaming:common",
-    ]
-  }
 }