Update readme

Author: Neel Goyal

README.md

@@ -6,6 +6,21 @@ WHATS:
 
   Go bindings for V8
 
+UPDATE for V8 3.21
+------------------
+
+Only got this going against v8 for OSX.  Build V8 for OSX as described by https://code.google.com/p/v8/wiki/BuildingWithGYP
+Copy $(V8SRCROOT)/include/ files to /usr/local/include
+Copy $(V8SRCROOT)/native/out/libv8\* files to /usr/local/lib
+
+'''
+go test
+# testmain
+github.com/mattn/go-v8(__DATA/__datacoal_nt): unexpected reloc for dynamic symbol _ZTVN10__cxxabiv117__class_type_infoE
+github.com/mattn/go-v8(__DATA/__datacoal_nt): unhandled relocation for _ZTVN10__cxxabiv117__class_type_infoE (type 28 rtype 120)
+FAIL    github.com/mattn/go-v8 [build failed]
+'''
+
 INSTALL:
 --------