//breakpad:symuploader should only compile with the host toolchain.

BUILD.gn

 # Copyright (c) 2013 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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 520 matching lines @@
       "//third_party/codesighs:msmap2tsv",
       "//third_party/pdfium/samples:pdfium_diff",
       "//ui/metro_viewer",
     ]
     deps -= [
       "//crypto:crypto_unittests",  # TODO(GYP)
       "//net:net_unittests",  # TODO(GYP)
     ]
   } else if (!is_android && !is_ios) {
     deps += [
-      "//breakpad:symupload",
+      "//breakpad:symupload($host_toolchain)",
       "//media/cast:cast_unittests",
     ]
   }
 }
 
 group("gn_only") {
   testonly = true
 
   deps = []
 
@@ skipping 244 matching lines @@
       if (target_cpu == "x86") {
         deps += [
           # "//content/shell:crash_service_win64", TODO(GYP): crbug.com/537009
         ]
       }
     } else {
       deps += [ "//breakpad:minidump_stackwalk($host_toolchain)" ]
     }
   }
 }