[Android] Support compiling with NDK r13b.

build/config/android/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.
 
 import("//build/config/android/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
 assert(is_android)
 
 # This is included by reference in the //build/config/compiler config that
@@ skipping 78 matching lines @@
 # config that is applied to all targets. It is here to separate out the logic
 # that is Android-only. Please see that target for advice on what should go in
 # :runtime_library vs. :compiler.
 config("runtime_library") {
   # NOTE: The libc++ header include paths below are specified in cflags_cc
   # rather than include_dirs because they need to come after include_dirs.
   # Think of them like system headers, but don't use '-isystem' because the
   # arm-linux-androideabi-4.4.3 toolchain (circa Gingerbread) will exhibit
   # strange errors. The include ordering here is important; change with
   # caution.
-  cflags_cc = [
-    "-isystem" +
-        rebase_path("$android_libcpp_root/libcxx/include", root_build_dir),
-    "-isystem" + rebase_path(
+  cflags_cc = []
+  if (android_ndk_major_version >= 13) {
+    libcxx_include_path =
+        rebase_path("$android_libcpp_root/include", root_build_dir)
+    libcxxabi_include_path =
+        rebase_path("$android_ndk_root/sources/cxx-stl/llvm-libc++abi/include",
+                    root_build_dir)
+
+    if (!is_clang) {
+      # Per the release notes, GCC is not supported in the NDK starting with
+      # r13. It's still present, though, and has conflicting declarations of
+      # float abs(float).
+      cflags_cc += [ "-Wno-attributes" ]
+    }
+  } else {
+    libcxx_include_path =
+        rebase_path("$android_libcpp_root/libcxx/include", root_build_dir)
+    libcxxabi_include_path = rebase_path(
             "$android_ndk_root/sources/cxx-stl/llvm-libc++abi/libcxxabi/include",
-            root_build_dir),
+            root_build_dir)
+  }
+  cflags_cc += [
+    "-isystem" + libcxx_include_path,
+    "-isystem" + libcxxabi_include_path,
     "-isystem" +
         rebase_path("$android_ndk_root/sources/android/support/include",
                     root_build_dir),
   ]
 
   defines = [ "__GNU_SOURCE=1" ]  # Necessary for clone().
   ldflags = [ "-nostdlib" ]
   lib_dirs = [ android_libcpp_lib_dir ]
 
   # The libc++ runtime library (must come first).
@@ skipping 95 matching lines @@
 
       # Avoid errors with current NDK:
       # "third_party/android_tools/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/include/arm_neon.h:3426:3: error: argument must be a constant"
       "-finstrument-functions-exclude-file-list=arm_neon.h",
     ]
   }
 }
 
 config("no_cygprofile_instrumentation") {
 }