Only pass android_toolchain in android builds.

dl/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 
 declare_args() {
   # Override this value to build with small float FFT tables
   openmax_big_float_fft = true
 }
 
 config("dl_config") {
   include_dirs = [ ".." ]
   if (current_cpu == "arm") {
     if (arm_use_neon) {
       # Enable build-time NEON selection.
       defines = [ "DL_ARM_NEON" ]
     } else if (arm_optionally_use_neon) {
       # Enable run-time NEON selection.
       defines = [ "DL_ARM_NEON_OPTIONAL" ]
     }
   } else if (current_cpu == "arm64") {
     # Enable build-time NEON selection.
     defines = [ "DL_ARM_NEON" ]
   }
 
   if (current_cpu == "arm" && is_clang) {
     # TODO(hans) Enable integrated-as (crbug.com/124610).
-    rebased_android_toolchain_root =
-        rebase_path(android_toolchain_root, root_build_dir)
-    asmflags = [
-      "-fno-integrated-as",
-      "-B${rebased_android_toolchain_root}/bin",  # Else /usr/bin/as gets picked up.
-    ]
+    asmflags = [ "-fno-integrated-as" ]
+    if (is_android) {
+      rebased_android_toolchain_root =
+          rebase_path(android_toolchain_root, root_build_dir)
+      # Else /usr/bin/as gets picked up.
+      asmflags += [ "-B${rebased_android_toolchain_root}/bin" ]
+    }
   }
 }
 
 # GYP: third_party/openmax_dl/dl/dl.gyp:openmax_dl
 source_set("dl") {
   public_configs = [ ":dl_config" ]
   sources = [
     "api/omxtypes.h",
     "sp/api/omxSP.h",
     "sp/src/armSP_FFT_F32TwiddleTable.c",
@@ skipping 214 matching lines @@
       "sp/src/arm/neon/omxSP_FFTFwd_CToC_FC32_Sfs_s.S",
       "sp/src/arm/neon/omxSP_FFTInv_CToC_FC32_Sfs_s.S",
 
       # Real floating-point FFT
       "sp/src/arm/neon/armSP_FFTInv_CCSToR_F32_preTwiddleRadix2_unsafe_s.S",
       "sp/src/arm/neon/omxSP_FFTFwd_RToCCS_F32_Sfs_s.S",
       "sp/src/arm/neon/omxSP_FFTInv_CCSToR_F32_Sfs_s.S",
     ]
   }
 }