Improve `gyp-to-cmake` to handle "dependencies"

[kraenhansen]

As per https://gyp.gsrc.io/docs/UserDocumentation.md

'dependencies': This lists other targets that this target depends on. The gyp-generated files will guarantee that the other targets are built before this target. Any library targets in the dependencies list will be linked with this target. The various settings (defines, include_dirs, etc.) listed in the direct_dependent_settings sections of the targets in this list will be applied to how this target is built and linked. See the more complete discussion of direct_dependent_settings, below.