Prefix build targets with /t: on Windows
Prefix build targets with /t: on Windows

Currently, on non-Windows platforms, it is possible to have
a multi-target native module and specify building just some
of the targets using `node-gyp build my_target`.

On Windows, however, specifying the targets to build requires the `/t:`
or `/target:` flag. Without this change you will get an `MSB1008` error
because MSBuild thinks you are trying to specify multiple solutions.

PR-URL: https://github.com/nodejs/node-gyp/pull/1164
Reviewed-By: Ben Noordhuis <59bd0a3ff43b32849b319e645d4798d8a5d1e889@bnoordhuis.nl>

nodejs/node-gyp,nodejs/node-gyp,nodejs/node-gyp,nodegit/node-gyp,nodegit/node-gyp,nodegit/node-gyp,nodegit/node-gyp,nodegit/node-gyp,nodejs/node-gyp,nodejs/node-gyp