Can't find node-gyp

[jjppof]

Windows 7 node 6.9 npm 3.10.8 python 2.7 node-gyp 3.6.2 VS Build tools 2015

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When installing msgpack, I'm getting this error:

I've already set npm_config_node_gyp as env var with C:\Users\[me]\AppData\Roaming\npm\node_modules\node-gyp\bin\node-gyp.js as value.

My node-gyp command works fine.

What am I missing? The msbuild is not even called.

I tried installing in another computer (a Win10 one), worked fine...