GN: Change rtc_source_set targets --> rtc_static_library

webrtc/sdk/BUILD.gn

 # Copyright 2016 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("../build/webrtc.gni")
 if (is_mac) {
   import("//build/config/mac/mac_sdk.gni")
   import("//build/config/mac/rules.gni")
 }
 if (is_ios) {
   import("//build/config/ios/rules.gni")
 }
 
 if (is_ios || (is_mac && mac_deployment_target == "10.7")) {
   config("rtc_sdk_common_objc_config") {
     include_dirs = [
       "objc/Framework/Classes",
       "objc/Framework/Headers",
     ]
   }
 
-  rtc_source_set("rtc_sdk_common_objc") {
+  rtc_static_library("rtc_sdk_common_objc") {
     deps = [
       "../base:rtc_base",
     ]
     configs += [ "//build/config/compiler:enable_arc" ]
     public_configs = [ ":rtc_sdk_common_objc_config" ]
     sources = [
       "objc/Framework/Classes/NSString+StdString.h",
       "objc/Framework/Classes/NSString+StdString.mm",
       "objc/Framework/Classes/RTCDispatcher.m",
       "objc/Framework/Classes/RTCFieldTrials.mm",
@@ skipping 33 matching lines @@
 
   config("rtc_sdk_peerconnection_objc_warnings_config") {
     if (is_clang) {
       # TODO(tkchin): Make rtc_sdk_peerconnection_objc compile with the standard
       # set of warnings.
       # See https://bugs.chromium.org/p/webrtc/issues/detail?id=6308
       cflags = [ "-Wno-thread-safety-analysis" ]
     }
   }
 
-  rtc_source_set("rtc_sdk_peerconnection_objc") {
+  rtc_static_library("rtc_sdk_peerconnection_objc") {
     sources = [
       "objc/Framework/Classes/RTCAVFoundationVideoSource+Private.h",
       "objc/Framework/Classes/RTCAVFoundationVideoSource.mm",
       "objc/Framework/Classes/RTCAudioSource+Private.h",
       "objc/Framework/Classes/RTCAudioSource.mm",
       "objc/Framework/Classes/RTCAudioTrack+Private.h",
       "objc/Framework/Classes/RTCAudioTrack.mm",
       "objc/Framework/Classes/RTCConfiguration+Private.h",
       "objc/Framework/Classes/RTCConfiguration.mm",
       "objc/Framework/Classes/RTCDataChannel+Private.h",
@@ skipping 242 matching lines @@
       public_configs = [ ":rtc_sdk_common_objc_config" ]
 
       if (is_clang) {
         # Suppress warnings from the Chromium Clang plugins.
         # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
         configs -= [ "//build/config/clang:find_bad_constructs" ]
       }
     }
   }
 }