Building native extensions.  This could take a while...
ERROR:  Error installing therubyracer:
    ERROR: Failed to build gem native extension.

    /Users/karl/.rbenv/versions/2.2.2/bin/ruby -r ./siteconf20150714-54941-u2qv6y.rb extconf.rb
checking for main() in -lpthread... yes
checking for main() in -lobjc... yes
checking for v8.h... yes
checking for main() in -lv8... yes
creating Makefile

make "DESTDIR=" clean

make "DESTDIR="
compiling accessor.cc
clang: warning: argument unused during compilation: '-rdynamic'
In file included from accessor.cc:1:
In file included from ./rr.h:4:
/usr/local/include/v8.h:3915:36: error: 'v8::PropertyHandlerFlags' is not a class, namespace, or scoped enumeration
      PropertyHandlerFlags flags = PropertyHandlerFlags::kNone)
                                   ^
/usr/local/include/v8.h:3943:36: error: 'v8::PropertyHandlerFlags' is not a class, namespace, or scoped enumeration
      PropertyHandlerFlags flags = PropertyHandlerFlags::kNone)
                                   ^
In file included from accessor.cc:1:
./rr.h:358:39: error: no member named 'ScriptData' in namespace 'v8'
class ScriptData : public Pointer<v8::ScriptData> {
                                  ~~~~^
./rr.h:358:51: error: expected class name
class ScriptData : public Pointer<v8::ScriptData> {
                                                  ^
./rr.h:360:21: error: no type named 'ScriptData' in namespace 'v8'; did you mean simply 'ScriptData'?
  inline ScriptData(v8::ScriptData* d) : Pointer<v8::ScriptData>(d) {};
                    ^~~~~~~~~~~~~~
                    ScriptData
./rr.h:358:7: note: 'ScriptData' declared here
class ScriptData : public Pointer<v8::ScriptData> {
      ^
./rr.h:360:54: error: no member named 'ScriptData' in namespace 'v8'
  inline ScriptData(v8::ScriptData* d) : Pointer<v8::ScriptData>(d) {};
                                                 ~~~~^
./rr.h:360:65: error: expected class member or base class name
  inline ScriptData(v8::ScriptData* d) : Pointer<v8::ScriptData>(d) {};
                                                                ^
./rr.h:360:65: error: expected '{' or ','
./rr.h:361:48: error: no member named 'ScriptData' in namespace 'v8'
  inline ScriptData(VALUE value) : Pointer<v8::ScriptData>(value) {}
                                           ~~~~^
./rr.h:361:59: error: expected class member or base class name
  inline ScriptData(VALUE value) : Pointer<v8::ScriptData>(value) {}
                                                          ^
./rr.h:361:59: error: expected '{' or ','
./rr.h:463:14: error: no type named 'AccessorGetter' in namespace 'v8'
  inline v8::AccessorGetter accessorGetter() {return &AccessorGetter;}
         ~~~~^
./rr.h:464:14: error: no type named 'AccessorSetter' in namespace 'v8'
  inline v8::AccessorSetter accessorSetter() {return RTEST(set) ? &AccessorSetter : 0;}
         ~~~~^
./rr.h:466:14: error: no type named 'NamedPropertyGetter' in namespace 'v8'
  inline v8::NamedPropertyGetter namedPropertyGetter() {return &NamedPropertyGetter;}
         ~~~~^
./rr.h:467:14: error: no type named 'NamedPropertySetter' in namespace 'v8'
  inline v8::NamedPropertySetter namedPropertySetter() {return RTEST(set) ? &NamedPropertySetter : 0;}
         ~~~~^
./rr.h:468:14: error: no type named 'NamedPropertyQuery' in namespace 'v8'
  inline v8::NamedPropertyQuery namedPropertyQuery() {return RTEST(query) ? &NamedPropertyQuery : 0;}
         ~~~~^
./rr.h:469:14: error: no type named 'NamedPropertyDeleter' in namespace 'v8'
  inline v8::NamedPropertyDeleter namedPropertyDeleter() {return RTEST(deleter) ? &NamedPropertyDeleter : 0;}
         ~~~~^
./rr.h:470:14: error: no type named 'NamedPropertyEnumerator' in namespace 'v8'
  inline v8::NamedPropertyEnumerator namedPropertyEnumerator() {return RTEST(enumerator) ? &NamedPropertyEnumerator : 0;}
         ~~~~^
./rr.h:472:14: error: no type named 'IndexedPropertyGetter' in namespace 'v8'
  inline v8::IndexedPropertyGetter indexedPropertyGetter() {return &IndexedPropertyGetter;}
         ~~~~^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.
make: *** [accessor.o] Error 1

make failed, exit code 2

Gem files will remain installed in /Users/karl/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/therubyracer-0.12.2 for inspection.
Results logged to /Users/karl/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/extensions/x86_64-darwin-15/2.2.0-static/therubyracer-0.12.2/gem_make.out