Add RLZ build file for GN build, fix Windows build.

tools/gn/secondary/third_party/icu/BUILD.gn

 # Copyright (c) 2012 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.
 
 # Meta target that includes both icuuc and icui18n. Most targets want both.
 # You can depend on the individually if you need to.
 group("icu") {
   deps = [
     ":icui18n",
     ":icuuc",
   ]
 }
 
 # Shared config used by ICU and all dependents.
 config("icu_config") {
   defines = [
     "U_USING_ICU_NAMESPACE=0",
   ]
+
+  if (component_mode != "shared_library") {
+    defines += [ "U_STATIC_IMPLEMENTATION" ]
+  }
+
   include_dirs = [
     "source/common",
     "source/i18n",
   ]
 }
 
 # Config used only by ICU code.
 config("icu_code") {
-  if (component_mode != "shared_library") {
-    defines = [ "U_STATIC_IMPLEMENTATION" ]
-  }
-
   if (is_win) {
     # Disable some compiler warnings.
     cflags = [
       "/wd4005",  # Macro redefinition.
       "/wd4068",  # Unknown pragmas.
       "/wd4267",  # Conversion from size_t on 64-bits.
       "/wd4996",  # Deprecated functions.
     ]
   } else if (is_linux) {
     cflags = [
@@ skipping 393 matching lines @@
       # the icudt46_dat symbol.
       "android/icudt46l_dat.S",
       "linux/icudt46l_dat.S",
       "mac/icudt46l_dat.S",
     ]
     defines = [ "U_HIDE_DATA_SYMBOL" ]
 
     # TODO(brettw) support use_system_icu and icu_use_data_file_flag.
   }
 }