Enables GN build on windows

runtime/bin/BUILD.gn

 # Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 declare_args() {
   # Whether to fall back to built-in root certificates when they cannot be
   # verified at the operating system level.
   dart_use_fallback_root_certificates = false
 
   # The BUILD.gn file that we pull from chromium as part of zlib has a
@@ skipping 185 matching lines @@
 }
 
 gen_library_src_path("generate_web_audio_cc_file") {
   name = "web_audio"
   kind = "source"
   sources = ["../../sdk/lib/web_audio/dartium/web_audio_dartium.dart"]
   output = "$target_gen_dir/web_audio_gen.cc"
 }
 
 config("libdart_builtin_config") {
-  libs = [
-    "dl",
-  ]
+  if (!is_win) {
+    libs = [
+      "dl",
+    ]
+  }
   if (is_android) {
     libs += [
       "android",
       "log",
     ]
   }
 }
 
 builtin_impl_sources_gypi =
     exec_script("../../tools/gypi_to_gn.py",
@@ skipping 74 matching lines @@
   include_dirs = [
     "..",
   ]
 
   if (is_mac) {
     libs = [
       "CoreFoundation.framework",
       "CoreServices.framework"
     ]
   }
+
+  if (is_win) {
+    libs = [
+      "iphlpapi.lib",
+      "psapi.lib",
+      "ws2_32.lib",
+      "Rpcrt4.lib",
+      "winmm.lib",
+    ]
+  }
 }
 
 # A source set for the implementation of 'dart:io' library
 # (without secure sockets) suitable for linking with gen_snapshot.
 source_set("gen_snapshot_dart_io") {
   configs += ["..:dart_config",
               "..:dart_maybe_product_config",
               "..:dart_precompiler_config"]
 
   deps = [
@@ skipping 225 matching lines @@
       "vmservice_impl.cc",
       "vmservice_impl.h",
       "$target_gen_dir/resources_gen.cc",
     ] + extra_sources
 
     include_dirs = [
       "..",
       "//third_party",
     ]
 
-    ldflags = [
-      "-rdynamic",
-    ]
+    if (is_win) {
+      ldflags = [
+        "/EXPORT:Dart_True"
+      ]
+    } else {
+      ldflags = [
+        "-rdynamic",
+      ]
+    }
+
+    if (is_win) {
+      libs = [
+        "iphlpapi.lib",
+        "psapi.lib",
+        "ws2_32.lib",
+        "Rpcrt4.lib",
+        "winmm.lib",
+      ]
+    }
   }
 }
 
 if (!defined(is_fuchsia) || !is_fuchsia) {
   dart_executable("dart") {
     extra_deps = [
       "..:libdart",
       ":dart_snapshot_cc",
       "../observatory:standalone_observatory_archive",
     ]
@@ skipping 151 matching lines @@
                   [rebase_path("builtin_impl_sources.gypi"),
                    "--keep_only=_test.cc",
                    "--keep_only=_test.h",],
                   "scope",
                   ["builtin_impl_sources.gypi"])
 
   sources = [
     "run_vm_tests.cc",
   ] + builtin_impl_tests_list.sources + vm_tests
 
-  ldflags = [
-    "-rdynamic",
-  ]
+  if (!is_win) {
+    ldflags = [
+      "-rdynamic",
+    ]
+  }
+
+  if (is_win) {
+    libs = [
+      "iphlpapi.lib",
+      "psapi.lib",
+      "ws2_32.lib",
+      "Rpcrt4.lib",
+      "winmm.lib",
+    ]
+  }
 }
 
 if (!defined(is_fuchsia) || !is_fuchsia) {
   shared_library("test_extension") {
     deps = [
       ":dart",
     ]
     sources = [
       "test_extension.c",
       "test_extension_dllmain_win.cc",
     ]
     include_dirs = [
       "..",
     ]
     defines = [
       # The only effect of DART_SHARED_LIB is to export the Dart API.
       "DART_SHARED_LIB",
     ]
+    if (is_win) {
+      libs = [
+        "dart.lib"
+      ]
+      abs_root_out_dir = rebase_path(root_out_dir)
+      ldflags = [
+        "/LIBPATH:$abs_root_out_dir"
+      ]
+    }
   }
 
   shared_library("sample_extension") {
     deps = [
       ":dart",
     ]
     sources = [
       "../../samples/sample_extension/sample_extension.cc",
       "../../samples/sample_extension/sample_extension_dllmain_win.cc",
     ]
     include_dirs = [
       "..",
     ]
     defines = [
       # The only effect of DART_SHARED_LIB is to export the Dart API.
       "DART_SHARED_LIB",
     ]
+    if (is_win) {
+      libs = [
+        "dart.lib"
+      ]
+      abs_root_out_dir = rebase_path(root_out_dir)
+      ldflags = [
+        "/LIBPATH:$abs_root_out_dir"
+      ]
+    }
   }
 }