Update V8 to r4730 as required by WebKit r60469
diff --git a/src/mips/debug-mips.cc b/src/mips/debug-mips.cc
index cdb35ae..8c40930 100644
--- a/src/mips/debug-mips.cc
+++ b/src/mips/debug-mips.cc
@@ -29,6 +29,8 @@
 
 #include "v8.h"
 
+#if defined(V8_TARGET_ARCH_MIPS)
+
 #include "codegen-inl.h"
 #include "debug.h"
 
@@ -126,3 +128,4 @@
 
 } }  // namespace v8::internal
 
+#endif  // V8_TARGET_ARCH_MIPS