Adjusted gtest-port.h to work when ANDROID is defined.

Removed from the makefile the explicit OS setting (was linux)
Added a new OS: Android.
When -DANDROID is specified during preprocessing, the right
includes should happen.
diff --git a/include/gtest/internal/gtest-port.h b/include/gtest/internal/gtest-port.h
index 11798a1..702ee63 100644
--- a/include/gtest/internal/gtest-port.h
+++ b/include/gtest/internal/gtest-port.h
@@ -65,6 +65,7 @@
 //
 // Macros indicating the current platform (defined to 1 if compiled on
 // the given platform; otherwise undefined):
+//   GTEST_OS_ANDROID  - Android
 //   GTEST_OS_CYGWIN   - Cygwin
 //   GTEST_OS_LINUX    - Linux
 //   GTEST_OS_MAC      - Mac OS X
@@ -177,6 +178,8 @@
 #define GTEST_OS_WINDOWS 1
 #elif defined __APPLE__
 #define GTEST_OS_MAC 1
+#elif defined ANDROID
+#define GTEST_OS_ANDROID 1
 #elif defined __linux__
 #define GTEST_OS_LINUX 1
 #elif defined __MVS__
@@ -250,10 +253,11 @@
 // TODO(wan@google.com): uses autoconf to detect whether ::std::wstring
 //   is available.
 
-#if GTEST_OS_CYGWIN || GTEST_OS_SOLARIS
+#if GTEST_OS_CYGWIN || GTEST_OS_SOLARIS || GTEST_OS_ANDROID
 // Cygwin 1.5 and below doesn't support ::std::wstring.
 // Cygwin 1.7 might add wstring support; this should be updated when clear.
 // Solaris' libc++ doesn't support it either.
+// Android does not support wstring and never will.
 #define GTEST_HAS_STD_WSTRING 0
 #else
 #define GTEST_HAS_STD_WSTRING GTEST_HAS_STD_STRING
@@ -379,7 +383,7 @@
 #if GTEST_HAS_STD_STRING && (GTEST_OS_LINUX || \
                              GTEST_OS_MAC || \
                              GTEST_OS_CYGWIN || \
-                             (GTEST_OS_WINDOWS && _MSC_VER >= 1400))
+                             (GTEST_OS_WINDOWS && _MSC_VER >= 1400)) && !GTEST_OS_ANDROID
 #define GTEST_HAS_DEATH_TEST 1
 #include <vector>
 #endif
diff --git a/src/Android.mk b/src/Android.mk
index cd98aa3..ec547c8 100644
--- a/src/Android.mk
+++ b/src/Android.mk
@@ -41,7 +41,7 @@
     $(LOCAL_PATH)/../include
 
 
-LOCAL_CFLAGS += -DGTEST_OS_LINUX -DGTEST_HAS_STD_STRING -O0
+LOCAL_CFLAGS += -O0
 
 LOCAL_MODULE := libgtest
 LOCAL_MODULE_TAGS := tests
@@ -63,7 +63,7 @@
     $(LOCAL_PATH)/.. \
     $(LOCAL_PATH)/../include
 
-LOCAL_CFLAGS += -DGTEST_OS_LINUX -DGTEST_HAS_STD_STRING -O0
+LOCAL_CFLAGS += -O0
 
 LOCAL_STATIC_LIBRARIES := libgtest
 
diff --git a/test/Android.mk b/test/Android.mk
index 3238f27..1f399d6 100644
--- a/test/Android.mk
+++ b/test/Android.mk
@@ -38,7 +38,7 @@
 endef
 
 define host-test
-$(call _define-test,$(1),HOST_,-DGTEST_OS_LINUX -DGTEST_HAS_STD_STRING -O0)
+$(call _define-test,$(1),HOST_,-O0)
 endef
 
 # TODO: Figure out the right CFLAGS combination needed for bionic/astl.