iSAC: Remove unnecessary WEBRTC_LINUX define

webrtc/modules/audio_coding/BUILD.gn

 # Copyright (c) 2014 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")
 import("audio_coding.gni")
@@ skipping 537 matching lines @@
     "codecs/isac/fix/source/pitch_lag_tables.c",
     "codecs/isac/fix/source/pitch_lag_tables.h",
     "codecs/isac/fix/source/settings.h",
     "codecs/isac/fix/source/spectrum_ar_model_tables.c",
     "codecs/isac/fix/source/spectrum_ar_model_tables.h",
     "codecs/isac/fix/source/structs.h",
     "codecs/isac/fix/source/transform.c",
     "codecs/isac/fix/source/transform_tables.c",
   ]
 
-  if (!is_win) {
-    defines = [ "WEBRTC_LINUX" ]
-  }
-
   public_configs = [ ":isac_fix_config" ]
 
   deps = [
     ":audio_decoder_interface",
     ":audio_encoder_interface",
     ":isac_common",
     "../../common_audio",
     "../../system_wrappers",
   ]
 
@@ skipping 994 matching lines @@
       "//testing/gtest",
     ]
 
     if (is_clang) {
       # Suppress warnings from Chrome's Clang plugins.
       # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
   }
 }