From 7b637ebdc97655462d08d8ff70bee5d4f32e4681 Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Tue, 23 Aug 2016 13:08:53 -0400
Subject: [PATCH] Android: Add `ANDROID` variable to indicate the target

Allow projects to use `if(ANDROID)` to condition their Android-specific
code paths.
---
 Help/manual/cmake-variables.7.rst   | 1 +
 Help/variable/ANDROID.rst           | 5 +++++
 Modules/Platform/Android.cmake      | 2 ++
 Tests/RunCMake/Android/common.cmake | 4 ++++
 4 files changed, 12 insertions(+)
 create mode 100644 Help/variable/ANDROID.rst

diff --git a/Help/manual/cmake-variables.7.rst b/Help/manual/cmake-variables.7.rst
index cdce6f64e..275b66cec 100644
--- a/Help/manual/cmake-variables.7.rst
+++ b/Help/manual/cmake-variables.7.rst
@@ -173,6 +173,7 @@ Variables that Describe the System
 .. toctree::
    :maxdepth: 1
 
+   /variable/ANDROID
    /variable/APPLE
    /variable/BORLAND
    /variable/CMAKE_CL_64
diff --git a/Help/variable/ANDROID.rst b/Help/variable/ANDROID.rst
new file mode 100644
index 000000000..fede4caf3
--- /dev/null
+++ b/Help/variable/ANDROID.rst
@@ -0,0 +1,5 @@
+ANDROID
+-------
+
+Set to ``1`` when the target system (:variable:`CMAKE_SYSTEM_NAME`) is
+``Android``.
diff --git a/Modules/Platform/Android.cmake b/Modules/Platform/Android.cmake
index 1bdad0403..3d69733bb 100644
--- a/Modules/Platform/Android.cmake
+++ b/Modules/Platform/Android.cmake
@@ -1,5 +1,7 @@
 include(Platform/Linux)
 
+set(ANDROID 1)
+
 # Android has soname, but binary names must end in ".so" so we cannot append
 # a version number.  Also we cannot portably represent symlinks on the host.
 set(CMAKE_PLATFORM_NO_VERSIONED_SONAME 1)
diff --git a/Tests/RunCMake/Android/common.cmake b/Tests/RunCMake/Android/common.cmake
index a679f6c64..7eac5d613 100644
--- a/Tests/RunCMake/Android/common.cmake
+++ b/Tests/RunCMake/Android/common.cmake
@@ -1,6 +1,10 @@
 enable_language(C)
 enable_language(CXX)
 
+if(NOT ANDROID)
+  message(SEND_ERROR "CMake variable 'ANDROID' is not set to a true value.")
+endif()
+
 foreach(f
     "${CMAKE_C_ANDROID_TOOLCHAIN_PREFIX}gcc${CMAKE_C_ANDROID_TOOLCHAIN_SUFFIX}"
     "${CMAKE_CXX_ANDROID_TOOLCHAIN_PREFIX}g++${CMAKE_CXX_ANDROID_TOOLCHAIN_SUFFIX}"