The Reg* APIs on Windows don't use GetLastError() to report
failures. The errors are returned directly from the call.
For systems which don't have one of the values GetLastError() can
end up returning 0 to the caller, indicating success. The caller
then assumes that the data is valid and can attempt to execute on
garbage data. This change fixes the flow to correctly return the
error to the caller.
PR-URL: https://github.com/libuv/libuv/pull/1811
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>