diff --git a/tests/gtest/README.md b/tests/gtest/README.md
new file mode 100644
index 000000000..e0ea1b0f3
--- /dev/null
+++ b/tests/gtest/README.md
@@ -0,0 +1,280 @@
+
+### Generic Build Instructions ###
+
+#### Setup ####
+
+To build Google Test and your tests that use it, you need to tell your
+build system where to find its headers and source files.  The exact
+way to do it depends on which build system you use, and is usually
+straightforward.
+
+#### Build ####
+
+Suppose you put Google Test in directory `${GTEST_DIR}`.  To build it,
+create a library build target (or a project as called by Visual Studio
+and Xcode) to compile
+
+    ${GTEST_DIR}/src/gtest-all.cc
+
+with `${GTEST_DIR}/include` in the system header search path and `${GTEST_DIR}`
+in the normal header search path.  Assuming a Linux-like system and gcc,
+something like the following will do:
+
+    g++ -isystem ${GTEST_DIR}/include -I${GTEST_DIR} \
+        -pthread -c ${GTEST_DIR}/src/gtest-all.cc
+    ar -rv libgtest.a gtest-all.o
+
+(We need `-pthread` as Google Test uses threads.)
+
+Next, you should compile your test source file with
+`${GTEST_DIR}/include` in the system header search path, and link it
+with gtest and any other necessary libraries:
+
+    g++ -isystem ${GTEST_DIR}/include -pthread path/to/your_test.cc libgtest.a \
+        -o your_test
+
+As an example, the make/ directory contains a Makefile that you can
+use to build Google Test on systems where GNU make is available
+(e.g. Linux, Mac OS X, and Cygwin).  It doesn't try to build Google
+Test's own tests.  Instead, it just builds the Google Test library and
+a sample test.  You can use it as a starting point for your own build
+script.
+
+If the default settings are correct for your environment, the
+following commands should succeed:
+
+    cd ${GTEST_DIR}/make
+    make
+    ./sample1_unittest
+
+If you see errors, try to tweak the contents of `make/Makefile` to make
+them go away.  There are instructions in `make/Makefile` on how to do
+it.
+
+### Using CMake ###
+
+Google Test comes with a CMake build script (
+[CMakeLists.txt](CMakeLists.txt)) that can be used on a wide range of platforms ("C" stands for
+cross-platform.). If you don't have CMake installed already, you can
+download it for free from <http://www.cmake.org/>.
+
+CMake works by generating native makefiles or build projects that can
+be used in the compiler environment of your choice.  The typical
+workflow starts with:
+
+    mkdir mybuild       # Create a directory to hold the build output.
+    cd mybuild
+    cmake ${GTEST_DIR}  # Generate native build scripts.
+
+If you want to build Google Test's samples, you should replace the
+last command with
+
+    cmake -Dgtest_build_samples=ON ${GTEST_DIR}
+
+If you are on a \*nix system, you should now see a Makefile in the
+current directory.  Just type 'make' to build gtest.
+
+If you use Windows and have Visual Studio installed, a `gtest.sln` file
+and several `.vcproj` files will be created.  You can then build them
+using Visual Studio.
+
+On Mac OS X with Xcode installed, a `.xcodeproj` file will be generated.
+
+### Legacy Build Scripts ###
+
+Before settling on CMake, we have been providing hand-maintained build
+projects/scripts for Visual Studio, Xcode, and Autotools.  While we
+continue to provide them for convenience, they are not actively
+maintained any more.  We highly recommend that you follow the
+instructions in the previous two sections to integrate Google Test
+with your existing build system.
+
+If you still need to use the legacy build scripts, here's how:
+
+The msvc\ folder contains two solutions with Visual C++ projects.
+Open the `gtest.sln` or `gtest-md.sln` file using Visual Studio, and you
+are ready to build Google Test the same way you build any Visual
+Studio project.  Files that have names ending with -md use DLL
+versions of Microsoft runtime libraries (the /MD or the /MDd compiler
+option).  Files without that suffix use static versions of the runtime
+libraries (the /MT or the /MTd option).  Please note that one must use
+the same option to compile both gtest and the test code.  If you use
+Visual Studio 2005 or above, we recommend the -md version as /MD is
+the default for new projects in these versions of Visual Studio.
+
+On Mac OS X, open the `gtest.xcodeproj` in the `xcode/` folder using
+Xcode.  Build the "gtest" target.  The universal binary framework will
+end up in your selected build directory (selected in the Xcode
+"Preferences..." -> "Building" pane and defaults to xcode/build).
+Alternatively, at the command line, enter:
+
+    xcodebuild
+
+This will build the "Release" configuration of gtest.framework in your
+default build location.  See the "xcodebuild" man page for more
+information about building different configurations and building in
+different locations.
+
+If you wish to use the Google Test Xcode project with Xcode 4.x and
+above, you need to either:
+
+ * update the SDK configuration options in xcode/Config/General.xconfig.
+   Comment options `SDKROOT`, `MACOS_DEPLOYMENT_TARGET`, and `GCC_VERSION`. If
+   you choose this route you lose the ability to target earlier versions
+   of MacOS X.
+ * Install an SDK for an earlier version. This doesn't appear to be
+   supported by Apple, but has been reported to work
+   (http://stackoverflow.com/questions/5378518).
+
+### Tweaking Google Test ###
+
+Google Test can be used in diverse environments.  The default
+configuration may not work (or may not work well) out of the box in
+some environments.  However, you can easily tweak Google Test by
+defining control macros on the compiler command line.  Generally,
+these macros are named like `GTEST_XYZ` and you define them to either 1
+or 0 to enable or disable a certain feature.
+
+We list the most frequently used macros below.  For a complete list,
+see file [include/gtest/internal/gtest-port.h](include/gtest/internal/gtest-port.h).
+
+### Choosing a TR1 Tuple Library ###
+
+Some Google Test features require the C++ Technical Report 1 (TR1)
+tuple library, which is not yet available with all compilers.  The
+good news is that Google Test implements a subset of TR1 tuple that's
+enough for its own need, and will automatically use this when the
+compiler doesn't provide TR1 tuple.
+
+Usually you don't need to care about which tuple library Google Test
+uses.  However, if your project already uses TR1 tuple, you need to
+tell Google Test to use the same TR1 tuple library the rest of your
+project uses, or the two tuple implementations will clash.  To do
+that, add
+
+    -DGTEST_USE_OWN_TR1_TUPLE=0
+
+to the compiler flags while compiling Google Test and your tests.  If
+you want to force Google Test to use its own tuple library, just add
+
+    -DGTEST_USE_OWN_TR1_TUPLE=1
+
+to the compiler flags instead.
+
+If you don't want Google Test to use tuple at all, add
+
+    -DGTEST_HAS_TR1_TUPLE=0
+
+and all features using tuple will be disabled.
+
+### Multi-threaded Tests ###
+
+Google Test is thread-safe where the pthread library is available.
+After `#include "gtest/gtest.h"`, you can check the `GTEST_IS_THREADSAFE`
+macro to see whether this is the case (yes if the macro is `#defined` to
+1, no if it's undefined.).
+
+If Google Test doesn't correctly detect whether pthread is available
+in your environment, you can force it with
+
+    -DGTEST_HAS_PTHREAD=1
+
+or
+
+    -DGTEST_HAS_PTHREAD=0
+
+When Google Test uses pthread, you may need to add flags to your
+compiler and/or linker to select the pthread library, or you'll get
+link errors.  If you use the CMake script or the deprecated Autotools
+script, this is taken care of for you.  If you use your own build
+script, you'll need to read your compiler and linker's manual to
+figure out what flags to add.
+
+### As a Shared Library (DLL) ###
+
+Google Test is compact, so most users can build and link it as a
+static library for the simplicity.  You can choose to use Google Test
+as a shared library (known as a DLL on Windows) if you prefer.
+
+To compile *gtest* as a shared library, add
+
+    -DGTEST_CREATE_SHARED_LIBRARY=1
+
+to the compiler flags.  You'll also need to tell the linker to produce
+a shared library instead - consult your linker's manual for how to do
+it.
+
+To compile your *tests* that use the gtest shared library, add
+
+    -DGTEST_LINKED_AS_SHARED_LIBRARY=1
+
+to the compiler flags.
+
+Note: while the above steps aren't technically necessary today when
+using some compilers (e.g. GCC), they may become necessary in the
+future, if we decide to improve the speed of loading the library (see
+<http://gcc.gnu.org/wiki/Visibility> for details).  Therefore you are
+recommended to always add the above flags when using Google Test as a
+shared library.  Otherwise a future release of Google Test may break
+your build script.
+
+### Avoiding Macro Name Clashes ###
+
+In C++, macros don't obey namespaces.  Therefore two libraries that
+both define a macro of the same name will clash if you #include both
+definitions.  In case a Google Test macro clashes with another
+library, you can force Google Test to rename its macro to avoid the
+conflict.
+
+Specifically, if both Google Test and some other code define macro
+FOO, you can add
+
+    -DGTEST_DONT_DEFINE_FOO=1
+
+to the compiler flags to tell Google Test to change the macro's name
+from `FOO` to `GTEST_FOO`.  Currently `FOO` can be `FAIL`, `SUCCEED`,
+or `TEST`.  For example, with `-DGTEST_DONT_DEFINE_TEST=1`, you'll
+need to write
+
+    GTEST_TEST(SomeTest, DoesThis) { ... }
+
+instead of
+
+    TEST(SomeTest, DoesThis) { ... }
+
+in order to define a test.
+
+## Developing Google Test ##
+
+This section discusses how to make your own changes to Google Test.
+
+### Testing Google Test Itself ###
+
+To make sure your changes work as intended and don't break existing
+functionality, you'll want to compile and run Google Test's own tests.
+For that you can use CMake:
+
+    mkdir mybuild
+    cd mybuild
+    cmake -Dgtest_build_tests=ON ${GTEST_DIR}
+
+Make sure you have Python installed, as some of Google Test's tests
+are written in Python.  If the cmake command complains about not being
+able to find Python (`Could NOT find PythonInterp (missing:
+PYTHON_EXECUTABLE)`), try telling it explicitly where your Python
+executable can be found:
+
+    cmake -DPYTHON_EXECUTABLE=path/to/python -Dgtest_build_tests=ON ${GTEST_DIR}
+
+Next, you can build Google Test and all of its own tests.  On \*nix,
+this is usually done by 'make'.  To run the tests, do
+
+    make test
+
+All tests should pass.
+
+Normally you don't need to worry about regenerating the source files,
+unless you need to modify them.  In that case, you should modify the
+corresponding .pump files instead and run the pump.py Python script to
+regenerate them.  You can find pump.py in the [scripts/](scripts/) directory.
+Read the [Pump manual](docs/PumpManual.md) for how to use it.
diff --git a/tests/gtest/include/gtest/internal/custom/gtest-port.h b/tests/gtest/include/gtest/internal/custom/gtest-port.h
new file mode 100644
index 000000000..7e744bd3b
--- /dev/null
+++ b/tests/gtest/include/gtest/internal/custom/gtest-port.h
@@ -0,0 +1,69 @@
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Injection point for custom user configurations.
+// The following macros can be defined:
+//
+//   Flag related macros:
+//     GTEST_FLAG(flag_name)
+//     GTEST_USE_OWN_FLAGFILE_FLAG_  - Define to 0 when the system provides its
+//                                     own flagfile flag parsing.
+//     GTEST_DECLARE_bool_(name)
+//     GTEST_DECLARE_int32_(name)
+//     GTEST_DECLARE_string_(name)
+//     GTEST_DEFINE_bool_(name, default_val, doc)
+//     GTEST_DEFINE_int32_(name, default_val, doc)
+//     GTEST_DEFINE_string_(name, default_val, doc)
+//
+//   Test filtering:
+//     GTEST_TEST_FILTER_ENV_VAR_ - The name of an environment variable that
+//                                  will be used if --GTEST_FLAG(test_filter)
+//                                  is not provided.
+//
+//   Logging:
+//     GTEST_LOG_(severity)
+//     GTEST_CHECK_(condition)
+//     Functions LogToStderr() and FlushInfoLog() have to be provided too.
+//
+//   Threading:
+//     GTEST_HAS_NOTIFICATION_ - Enabled if Notification is already provided.
+//     GTEST_HAS_MUTEX_AND_THREAD_LOCAL_ - Enabled if Mutex and ThreadLocal are
+//                                         already provided.
+//     Must also provide GTEST_DECLARE_STATIC_MUTEX_(mutex) and
+//     GTEST_DEFINE_STATIC_MUTEX_(mutex)
+//
+//     GTEST_EXCLUSIVE_LOCK_REQUIRED_(locks)
+//     GTEST_LOCK_EXCLUDED_(locks)
+//
+// ** Custom implementation starts here **
+
+#ifndef GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PORT_H_
+#define GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PORT_H_
+
+#endif  // GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PORT_H_
diff --git a/tests/gtest/include/gtest/internal/custom/gtest-printers.h b/tests/gtest/include/gtest/internal/custom/gtest-printers.h
new file mode 100644
index 000000000..60c1ea050
--- /dev/null
+++ b/tests/gtest/include/gtest/internal/custom/gtest-printers.h
@@ -0,0 +1,42 @@
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// This file provides an injection point for custom printers in a local
+// installation of gTest.
+// It will be included from gtest-printers.h and the overrides in this file
+// will be visible to everyone.
+// See documentation at gtest/gtest-printers.h for details on how to define a
+// custom printer.
+//
+// ** Custom implementation starts here **
+
+#ifndef GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PRINTERS_H_
+#define GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PRINTERS_H_
+
+#endif  // GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PRINTERS_H_
diff --git a/tests/gtest/include/gtest/internal/custom/gtest.h b/tests/gtest/include/gtest/internal/custom/gtest.h
new file mode 100644
index 000000000..c27412a89
--- /dev/null
+++ b/tests/gtest/include/gtest/internal/custom/gtest.h
@@ -0,0 +1,41 @@
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Injection point for custom user configurations.
+// The following macros can be defined:
+//
+// GTEST_OS_STACK_TRACE_GETTER_  - The name of an implementation of
+//                                 OsStackTraceGetterInterface.
+//
+// ** Custom implementation starts here **
+
+#ifndef GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_H_
+#define GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_H_
+
+#endif  // GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_H_
diff --git a/tests/gtest/include/gtest/internal/gtest-port-arch.h b/tests/gtest/include/gtest/internal/gtest-port-arch.h
new file mode 100644
index 000000000..74ab94905
--- /dev/null
+++ b/tests/gtest/include/gtest/internal/gtest-port-arch.h
@@ -0,0 +1,93 @@
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// The Google C++ Testing Framework (Google Test)
+//
+// This header file defines the GTEST_OS_* macro.
+// It is separate from gtest-port.h so that custom/gtest-port.h can include it.
+
+#ifndef GTEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_ARCH_H_
+#define GTEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_ARCH_H_
+
+// Determines the platform on which Google Test is compiled.
+#ifdef __CYGWIN__
+# define GTEST_OS_CYGWIN 1
+#elif defined __SYMBIAN32__
+# define GTEST_OS_SYMBIAN 1
+#elif defined _WIN32
+# define GTEST_OS_WINDOWS 1
+# ifdef _WIN32_WCE
+#  define GTEST_OS_WINDOWS_MOBILE 1
+# elif defined(__MINGW__) || defined(__MINGW32__)
+#  define GTEST_OS_WINDOWS_MINGW 1
+# elif defined(WINAPI_FAMILY)
+#  include <winapifamily.h>
+#  if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+#   define GTEST_OS_WINDOWS_DESKTOP 1
+#  elif WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_PHONE_APP)
+#   define GTEST_OS_WINDOWS_PHONE 1
+#  elif WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP)
+#   define GTEST_OS_WINDOWS_RT 1
+#  else
+    // WINAPI_FAMILY defined but no known partition matched.
+    // Default to desktop.
+#   define GTEST_OS_WINDOWS_DESKTOP 1
+#  endif
+# else
+#  define GTEST_OS_WINDOWS_DESKTOP 1
+# endif  // _WIN32_WCE
+#elif defined __APPLE__
+# define GTEST_OS_MAC 1
+# if TARGET_OS_IPHONE
+#  define GTEST_OS_IOS 1
+# endif
+#elif defined __FreeBSD__
+# define GTEST_OS_FREEBSD 1
+#elif defined __linux__
+# define GTEST_OS_LINUX 1
+# if defined __ANDROID__
+#  define GTEST_OS_LINUX_ANDROID 1
+# endif
+#elif defined __MVS__
+# define GTEST_OS_ZOS 1
+#elif defined(__sun) && defined(__SVR4)
+# define GTEST_OS_SOLARIS 1
+#elif defined(_AIX)
+# define GTEST_OS_AIX 1
+#elif defined(__hpux)
+# define GTEST_OS_HPUX 1
+#elif defined __native_client__
+# define GTEST_OS_NACL 1
+#elif defined __OpenBSD__
+# define GTEST_OS_OPENBSD 1
+#elif defined __QNX__
+# define GTEST_OS_QNX 1
+#endif  // __CYGWIN__
+
+#endif  // GTEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_ARCH_H_