For building v8 using gn on aix_ppc64, linux_s390x and linux_ppc64.

build/build_config.h

Index: build/build_config.h
diff --git a/build/build_config.h b/build/build_config.h
index fd5489f6459bedf3045a19cc3887821144a9eef6..f3f67f816e4270f3611a070042a150fcdc49a7aa 100644
--- a/build/build_config.h
+++ b/build/build_config.h
@@ -59,6 +59,8 @@
 #define OS_SOLARIS 1
 #elif defined(__QNXNTO__)
 #define OS_QNX 1
+#elif defined(_AIX)
+#define OS_AIX 1
 #else
 #error Please add support for your platform in build/build_config.h
 #endif
@@ -75,10 +77,11 @@
 
 // For access to standard POSIXish features, use OS_POSIX instead of a
 // more specific macro.
-#if defined(OS_MACOSX) || defined(OS_LINUX) || defined(OS_FREEBSD) ||     \
-    defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_SOLARIS) ||   \
-    defined(OS_ANDROID) || defined(OS_OPENBSD) || defined(OS_SOLARIS) ||  \
-    defined(OS_ANDROID) || defined(OS_NACL) || defined(OS_QNX)
+#if defined(OS_MACOSX) || defined(OS_LINUX) || defined(OS_FREEBSD) ||    \
+    defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_SOLARIS) ||  \
+    defined(OS_ANDROID) || defined(OS_OPENBSD) || defined(OS_SOLARIS) || \
+    defined(OS_ANDROID) || defined(OS_NACL) || defined(OS_QNX) ||        \

[Dirk Pranke, 2017/04/14 01:29:02]

It seems like some of these checks are duplicated. Can you fix that?

[rayb, 2017/04/25 00:41:03]

Done.

+    defined(OS_AIX)
 #define OS_POSIX 1
 #endif