GN: Android Vulkan support

gn/BUILDCONFIG.gn

 # Copyright 2016 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # It's best to keep the names and defaults of is_foo flags consistent with Chrome.
 
 declare_args() {
   is_debug = true
   is_component_build = false
   ndk = ""
+  ndk_api = 0  # 0 == picked automatically for target_cpu.
   sanitize = ""
 }
 
 # Platform detection
 if (target_os == "") {
   target_os = host_os
   if (ndk != "") {
     target_os = "android"
   }
 }
@@ skipping 16 matching lines @@
 }
 if (current_cpu == "") {
   current_cpu = target_cpu
 }
 
 if (is_android) {
   ndk_host = ""
   ndk_target = ""
   ndk_platform = ""
   ndk_stdlib = ""
-  nkd_gccdir = ""
+  ndk_gccdir = ""
+
+  if (ndk_api == 0) {
+    ndk_api = 18
+    if (target_cpu == "arm64" || target_cpu == "mips64el" ||
+        target_cpu == "x64") {
+      ndk_api = 21
+    }
+  }
 
   if (host_os == "linux") {
     ndk_host = "linux-x86_64"
   } else if (host_os == "mac") {
     ndk_host = "darwin-x86_64"
   }
 
   if (target_cpu == "arm64") {
     ndk_target = "aarch64-linux-android"
-    ndk_platform = "android-21/arch-arm64"
+    ndk_platform = "android-${ndk_api}/arch-arm64"
     ndk_stdlib = "arm64-v8a"
     ndk_gccdir = ndk_target
   } else if (target_cpu == "arm") {
     ndk_target = "arm-linux-androideabi"
-    ndk_platform = "android-18/arch-arm"
+    ndk_platform = "android-${ndk_api}/arch-arm"
     ndk_stdlib = "armeabi-v7a"
     ndk_gccdir = ndk_target
   } else if (target_cpu == "mips64el") {
     ndk_target = "mips64el-linux-android"
-    ndk_platform = "android-21/arch-mips64"
+    ndk_platform = "android-${ndk_api}/arch-mips64"
     ndk_stdlib = "mips64"
     ndk_gccdir = ndk_target
   } else if (target_cpu == "mipsel") {
     ndk_target = "mipsel-linux-android"
-    ndk_platform = "android-18/arch-mips"
+    ndk_platform = "android-${ndk_api}/arch-mips"
     ndk_stdlib = "mips"
     ndk_gccdir = ndk_target
   } else if (target_cpu == "x64") {
     ndk_target = "x86_64-linux-android"
-    ndk_platform = "android-21/arch-x86_64"
+    ndk_platform = "android-${ndk_api}/arch-x86_64"
     ndk_stdlib = "x86_64"
     ndk_gccdir = ndk_stdlib
   } else if (target_cpu == "x86") {
     ndk_target = "i686-linux-android"
-    ndk_platform = "android-18/arch-x86"
+    ndk_platform = "android-${ndk_api}/arch-x86"
     ndk_stdlib = "x86"
     ndk_gccdir = ndk_stdlib
   }
 }
 
 # A component is either a static or a shared library.
 template("component") {
   _component_mode = "static_library"
   if (is_component_build) {
     _component_mode = "shared_library"
@@ skipping 31 matching lines @@
 
 set_defaults("component") {
   configs = default_configs
   if (!is_component_build) {
     complete_static_lib = true
   }
 }
 
 # For now, we support GCC-like toolchains, including Clang.
 set_default_toolchain("//gn:gcc_like")