The gyp_uv build script provided by libuv hardcode the path for gyp around the beginning.
If it was provided through easy_install or pip we could have it installed as a python library quite easily but it is not so I'm not sure if there is an easy way around.
gyp is kind of a hackish build system made by the guys at google for v8, and there is no real support or push for it to be a real build system outside of google.