GN: Make NaCl toolchains run on Windows host

build/config/nacl/rules.gni

 # Copyright 2015 The Native Client 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/features.gni")
 import("//build/config/nacl/config.gni")
 
 # Generate a nmf file
 #
 # Native Client Manifest (nmf) is a JSON file that tells the browser where to
@@ skipping 18 matching lines @@
                              "data_deps",
                              "executables",
                              "lib_prefix",
                              "nmf",
                              "nmfflags",
                              "public_deps",
                              "stage_dependencies",
                              "testonly",
                            ])
 
+    objdump = rebase_path("${nacl_toolprefix}objdump")
+    if (host_os == "win") {
+      objdump += ".exe"
+    }
+
     script = "//native_client_sdk/src/tools/create_nmf.py"
+    inputs = [
+      objdump,
+    ]
     sources = executables
     outputs = [
       nmf,
     ]
     if (is_nacl_glibc) {
       if (defined(stage_dependencies)) {
         nmfflags += [ "--stage-dependencies=" +
                       rebase_path(stage_dependencies, root_build_dir) ]
         lib_path = stage_dependencies
       } else {
@@ skipping 23 matching lines @@
       } else {
         nmfflags +=
             [ "--library-path=" + rebase_path("${nacl_toolchain_tooldir}/lib") ]
         data = [
           "${lib_path}/lib/",
         ]
       }
     }
     args = [
              "--no-default-libpath",
-             "--objdump=" + rebase_path("${nacl_toolprefix}objdump"),
+             "--objdump=" + objdump,
              "--output=" + rebase_path(nmf, root_build_dir),
            ] + nmfflags + rebase_path(sources, root_build_dir)
     if (is_nacl_glibc && current_cpu == "arm") {
       deps += [ "//native_client/src/untrusted/elf_loader:elf_loader" ]
     }
   }
 }
 
 # Generate a nmf file for Non-SFI tests
 #
@@ skipping 36 matching lines @@
     } else {
       arch = target_cpu
     }
     args = [
       "--program=" + rebase_path(executable, root_build_dir),
       "--arch=${arch}",
       "--output=" + rebase_path(nmf, root_build_dir),
     ]
   }
 }