Add Haiku platform support.

This allows googletest to recognize the Haiku operating system when
running tests in other projects.

googletest/include/gtest/internal/gtest-port-arch.h

@@ -100,6 +100,8 @@
 # define GTEST_OS_OPENBSD 1
 #elif defined __QNX__
 # define GTEST_OS_QNX 1
+#elif defined(__HAIKU__)
+# define GTEST_OS_HAIKU 1
 #endif  // __CYGWIN__
 
 #endif  // GTEST_INCLUDE_GTEST_INTERNAL_GTEST_PORT_ARCH_H_

googletest/include/gtest/internal/gtest-port.h

@@ -115,6 +115,7 @@
 //   GTEST_OS_CYGWIN   - Cygwin
 //   GTEST_OS_DRAGONFLY - DragonFlyBSD
 //   GTEST_OS_FREEBSD  - FreeBSD
+//   GTEST_OS_HAIKU    - Haiku
 //   GTEST_OS_FUCHSIA  - Fuchsia
 //   GTEST_OS_GNU_KFREEBSD - GNU/kFreeBSD
 //   GTEST_OS_HPUX     - HP-UX
@@ -459,7 +460,7 @@ typedef struct _RTL_CRITICAL_SECTION GTEST_CRITICAL_SECTION;
 // Solaris' libc++ doesn't support it either.  Android has
 // no support for it at least as recent as Froyo (2.2).
 # define GTEST_HAS_STD_WSTRING \
-    (!(GTEST_OS_LINUX_ANDROID || GTEST_OS_CYGWIN || GTEST_OS_SOLARIS))
+    (!(GTEST_OS_LINUX_ANDROID || GTEST_OS_CYGWIN || GTEST_OS_SOLARIS || GTEST_OS_HAIKU))
 
 #endif  // GTEST_HAS_STD_WSTRING
 
@@ -536,7 +537,8 @@ typedef struct _RTL_CRITICAL_SECTION GTEST_CRITICAL_SECTION;
 #define GTEST_HAS_PTHREAD                                             \
   (GTEST_OS_LINUX || GTEST_OS_MAC || GTEST_OS_HPUX || GTEST_OS_QNX || \
    GTEST_OS_FREEBSD || GTEST_OS_NACL || GTEST_OS_NETBSD || GTEST_OS_FUCHSIA || \
-   GTEST_OS_DRAGONFLY || GTEST_OS_GNU_KFREEBSD || GTEST_OS_OPENBSD)
+   GTEST_OS_DRAGONFLY || GTEST_OS_GNU_KFREEBSD || GTEST_OS_OPENBSD || \
+   GTEST_OS_HAIKU)
 #endif  // GTEST_HAS_PTHREAD
 
 #if GTEST_HAS_PTHREAD
@@ -596,7 +598,7 @@ typedef struct _RTL_CRITICAL_SECTION GTEST_CRITICAL_SECTION;
      GTEST_OS_WINDOWS_MINGW || GTEST_OS_AIX || GTEST_OS_HPUX || \
      GTEST_OS_OPENBSD || GTEST_OS_QNX || GTEST_OS_FREEBSD || \
      GTEST_OS_NETBSD || GTEST_OS_FUCHSIA || GTEST_OS_DRAGONFLY || \
-     GTEST_OS_GNU_KFREEBSD)
+     GTEST_OS_GNU_KFREEBSD || GTEST_OS_HAIKU)
 # define GTEST_HAS_DEATH_TEST 1
 #endif