Add GN build file for third_party hunspell library.

BUILD.gn

+# Copyright 2014 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.
+
+config("hunspell_config") {
+  defines = [
+    "HUNSPELL_STATIC",
+    "HUNSPELL_CHROME_CLIENT",
+    "USE_HUNSPELL",
+  ]
+}
+
+source_set("hunspell") {
+  sources = [
+    "google/bdict.cc",
+    "google/bdict.h",
+    "google/bdict_reader.cc",
+    "google/bdict_reader.h",
+    "google/bdict_writer.cc",
+    "google/bdict_writer.h",
+    "src/hunspell/affentry.cxx",
+    "src/hunspell/affentry.hxx",
+    "src/hunspell/affixmgr.cxx",
+    "src/hunspell/affixmgr.hxx",
+    "src/hunspell/atypes.hxx",
+    "src/hunspell/baseaffix.hxx",
+    "src/hunspell/csutil.cxx",
+    "src/hunspell/csutil.hxx",
+    "src/hunspell/dictmgr.cxx",
+    "src/hunspell/dictmgr.hxx",
+    "src/hunspell/filemgr.cxx",
+    "src/hunspell/filemgr.hxx",
+    "src/hunspell/hashmgr.cxx",
+    "src/hunspell/hashmgr.hxx",
+    "src/hunspell/htypes.hxx",
+    "src/hunspell/hunspell.cxx",
+    "src/hunspell/hunspell.h",
+    "src/hunspell/hunspell.hxx",
+    "src/hunspell/hunzip.cxx",
+    "src/hunspell/hunzip.hxx",
+    "src/hunspell/langnum.hxx",
+    "src/hunspell/phonet.cxx",
+    "src/hunspell/phonet.hxx",
+    "src/hunspell/replist.cxx",
+    "src/hunspell/replist.hxx",
+    "src/hunspell/suggestmgr.cxx",
+    "src/hunspell/suggestmgr.hxx",
+    "src/hunspell/utf_info.hxx",
+    "src/hunspell/w_char.hxx",
+    "src/parsers/textparser.cxx",
+    "src/parsers/textparser.hxx",
+  ]
+
+  direct_dependent_configs = [
+    ":hunspell_config",
+  ]
+
+  defines = [
+    "OPENOFFICEORG",
+  ]
+
+  deps = [
+    "//base",
+    "//third_party/icu"
+  ]
+
+  cflags = []
+
+  if (is_win) {
+    cflags += [
+      # TODO(jschuh): http://crbug.com/167187 size_t -> int
+      "/wd4267",
+    ]
+  }
+
+  if (is_posix && !is_mac) {
+    cflags += [
+      "-Wno-unused-value",
+      "-Wno-unused-variable",
+      "-Wno-write-strings",
+    ]
+  }
+
+  if (is_linux) {
+    cflags += [
+      # affentry.hxx has NULL as default parameter for a FLAG in two
+      # places.
+      "-Wno-conversion-null",
+    ]
+  }
+
+  if (is_clang) {
+    cflags += [
+      # affentry.cxx has one `while ((p = nextchar(p)));` parsing loop.
+      "-Wno-empty-body",
+      # affentry.hxx has NULL as default parameter for a FLAG in two
+      # places.
+      "-Wno-null-conversion",
+    ]
+  }
+}