win: Call clang-cl instead of clang-cl.exe when targeting win on a non-win host.

build/toolchain/win/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.
 
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/win/visual_studio_version.gni")
 import("//build/toolchain/goma.gni")
 import("//build/toolchain/toolchain.gni")
 
 # Should only be running on Windows.
@@ skipping 217 matching lines @@
       if (defined(invoker.is_clang)) {
         is_clang = invoker.is_clang
       }
 
       # This value needs to be passed through unchanged.
       host_toolchain = host_toolchain
     }
   }
 }
 
+if (host_os == "win") {
+  clang_cl = "clang-cl.exe"
+} else {
+  clang_cl = "clang-cl"
+}
+
 # 32-bit toolchains. Only define these when the target architecture is 32-bit
 # since we don't do any 32-bit cross compiles when targeting 64-bit (the
 # build does generate some 64-bit stuff from 32-bit target builds).
 if (target_cpu == "x86") {
   x86_toolchain_data = exec_script("setup_toolchain.py",
                                    [
                                      visual_studio_path,
                                      gyp_win_tool_path,
                                      windows_sdk_path,
                                      visual_studio_runtime_dirs,
                                      "x86",
                                    ],
                                    "scope")
 
   msvc_toolchain("x86") {
     environment = "environment.x86"
     toolchain_cpu = "x86"
     cl = "${goma_prefix}\"${x86_toolchain_data.vc_bin_dir}/cl.exe\""
     is_clang = false
   }
 
   msvc_toolchain("clang_x86") {
     environment = "environment.x86"
     toolchain_cpu = "x86"
     prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
                          root_build_dir)
-    cl = "${goma_prefix}$prefix/clang-cl.exe"
+    cl = "${goma_prefix}$prefix/${clang_cl}"
     toolchain_os = "win"
     is_clang = true
   }
 }
 
 # 64-bit toolchains.
 x64_toolchain_data = exec_script("setup_toolchain.py",
                                  [
                                    visual_studio_path,
                                    gyp_win_tool_path,
                                    windows_sdk_path,
                                    visual_studio_runtime_dirs,
                                    "x64",
                                  ],
                                  "scope")
 
 msvc_toolchain("x64") {
   environment = "environment.x64"
   toolchain_cpu = "x64"
   cl = "${goma_prefix}\"${x64_toolchain_data.vc_bin_dir}/cl.exe\""
   is_clang = false
 }
 
 msvc_toolchain("clang_x64") {
   environment = "environment.x64"
   toolchain_cpu = "x64"
   prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
                        root_build_dir)
-  cl = "${goma_prefix}$prefix/clang-cl.exe"
+  cl = "${goma_prefix}$prefix/${clang_cl}"
   toolchain_os = "win"
   is_clang = true
 }
 
 # WinRT toolchains. Only define these when targeting them.
 #
 # NOTE: This is currently broken because it references vc_bin_dir. brettw@
 # changed this around a bit, and I don't know what this should be set to
 # in terms of what setup_toolchain returns for a certain CPU architecture.
 if (target_os == "winrt_81" || target_os == "winrt_81_phone" ||
     target_os == "winrt_10") {
   msvc_toolchain("winrt_x86") {
     environment = "environment.winrt_x86"
     cl = "${goma_prefix}\"${vc_bin_dir}/cl.exe\""
     is_clang = false
 
     toolchain_cpu = "x86"
     toolchain_os = current_os
   }
 
   msvc_toolchain("winrt_x64") {
     environment = "environment.winrt_x64"
     cl = "${goma_prefix}\"${vc_bin_dir}/cl.exe\""
     is_clang = false
 
     toolchain_cpu = "x64"
     toolchain_os = current_os
   }
 }