@hyperair @b4n rather than making a [expletive deleted] mess of ifdefs, why not just make these separate plugins `WebHelper3` and `markdown3` as a first thought. It not like either plugin is in heavy/any development, so not many changes are likely to have to be copied between GTK2 and 3 versions. And the GTK2 version can quietly go away at a later date.
That way the luddite support is still in its own plugin for backward distros and "advanced" distros like Debian can distribute GTK3 versions :grin:
The m4 should prevent the building the GTK2 or GTK3 plugins based on the Geany its building against, and if someone manages to build both versions @b4n has made the version numbering system prevent loading of GTK2 plugins in GTK3 Geany and vice versa.