Config changes to support target_os="fuchsia"

build/build_config.h

Index: build/build_config.h
diff --git a/build/build_config.h b/build/build_config.h
index a672380b15765967db320068b237156ac82fb632..090641907bdb49f4906159472962b7493e225943 100644
--- a/build/build_config.h
+++ b/build/build_config.h
@@ -49,6 +49,8 @@
 #endif
 #elif defined(_WIN32)
 #define OS_WIN 1
+#elif defined(__Fuchsia__)
+#define OS_FUCHSIA 1
 #elif defined(__FreeBSD__)
 #define OS_FREEBSD 1
 #elif defined(__NetBSD__)
@@ -77,10 +79,10 @@
 
 // For access to standard POSIXish features, use OS_POSIX instead of a
 // more specific macro.
-#if defined(OS_AIX) || defined(OS_ANDROID) || defined(OS_FREEBSD) || \
-    defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_NACL) ||   \
-    defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_QNX) ||  \
-    defined(OS_SOLARIS)
+#if defined(OS_AIX) || defined(OS_ANDROID) || defined(OS_FREEBSD) ||  \
+    defined(OS_FUCHSIA) || defined(OS_LINUX) || defined(OS_MACOSX) || \
+    defined(OS_NACL) || defined(OS_NETBSD) || defined(OS_OPENBSD) ||  \
+    defined(OS_QNX) || defined(OS_SOLARIS)
 #define OS_POSIX 1
 #endif
 
@@ -165,12 +167,10 @@
 // Type detection for wchar_t.
 #if defined(OS_WIN)
 #define WCHAR_T_IS_UTF16
-#elif defined(OS_POSIX) && defined(COMPILER_GCC) && \
-    defined(__WCHAR_MAX__) && \
+#elif defined(OS_POSIX) && defined(COMPILER_GCC) && defined(__WCHAR_MAX__) && \
     (__WCHAR_MAX__ == 0x7fffffff || __WCHAR_MAX__ == 0xffffffff)
 #define WCHAR_T_IS_UTF32
-#elif defined(OS_POSIX) && defined(COMPILER_GCC) && \
-    defined(__WCHAR_MAX__) && \
+#elif defined(OS_POSIX) && defined(COMPILER_GCC) && defined(__WCHAR_MAX__) && \
     (__WCHAR_MAX__ == 0x7fff || __WCHAR_MAX__ == 0xffff)
 // On Posix, we'll detect short wchar_t, but projects aren't guaranteed to
 // compile in this mode (in particular, Chrome doesn't). This is intended for