Error install node-netroute on NetBSD

[TomFreudenberg]

The problem is not located on node-netroute but on node-gyp.

node-gyp returns OS = linux for NetBSD what is wrong.

I send a PR to them which hopefully gets merged.

See: nodejs/node-gyp#803

[TomFreudenberg]

I leave this issue opened here until the PR gets merged or the conditions in bindings.gyp must be modified.