npm install failed on Node.js 6 (on OSX)

[blai]

> node-gyp rebuild

gyp WARN download NVM_NODEJS_ORG_MIRROR is deprecated and will be removed in node-gyp v4, please use NODEJS_ORG_MIRROR
gyp WARN download NVM_NODEJS_ORG_MIRROR is deprecated and will be removed in node-gyp v4, please use NODEJS_ORG_MIRROR
gyp WARN download NVM_NODEJS_ORG_MIRROR is deprecated and will be removed in node-gyp v4, please use NODEJS_ORG_MIRROR
  CXX(target) Release/obj.target/binding/src/binding.o
In file included from ../src/binding.cc:7:
../../nan/nan.h:592:20: error: no type named 'GCEpilogueCallback' in 'v8::Isolate'
      v8::Isolate::GCEpilogueCallback callback
      ~~~~~~~~~~~~~^
../../nan/nan.h:598:20: error: no type named 'GCEpilogueCallback' in 'v8::Isolate'
      v8::Isolate::GCEpilogueCallback callback) {
      ~~~~~~~~~~~~~^
../../nan/nan.h:603:20: error: no type named 'GCPrologueCallback' in 'v8::Isolate'
      v8::Isolate::GCPrologueCallback callback
      ~~~~~~~~~~~~~^
../../nan/nan.h:609:20: error: no type named 'GCPrologueCallback' in 'v8::Isolate'
      v8::Isolate::GCPrologueCallback callback) {
      ~~~~~~~~~~~~~^
4 errors generated.
make: *** [Release/obj.target/binding/src/binding.o] Error 1

[blai]

I take this back. After tracing this for a little longer, I found that the root issue was dtrace-provider was forcing a lower version of nan, which causes the issue. chrisa/node-dtrace-provider#80