Specman/e: some features (e.g. “define macros”) require a working Specman installation.

Vera: a working Vera installation is normally required, as vzDoc makes use of the Vera preprocessor. (But the Vera preprocessor vera_pp is GPL'd -- a thinly disguised version of the GCC preprocessor -- so you can just use that directly. Use the temporary experimental environment variable VZDOC_VERA_PP to set up what you want to use.)