> But when you use autotools for extensions, then you still should to maintain it.
True, but the problem can be decomposed into two parts - maintaining for the core and maintaining for the extensions. At least core developers won't have to check if another patch compiles with Autotools.
Almost all server headers can be used in any extension. So I don't think maintaining autotools for extensions can be easier than maintaining autotools for the server.
I'm not certain what to do with the extensions. It seems that as long as we maintain Autotools the authors will have little interest in switching to Meson (or other build system - TimescaleDB for instance uses CMake; many modern extensions seem to be written in Rust with its own build system). Apparently we will have to start showing warnings at some point, and then finally drop Autotools. Unless we want to maintain it forever.
This being said, I didn't investigate how much effsqlort it will take to keep maintaining Autotools for extensions.
I support Meson in my extensions - Orafce and plpgsql_check, but unfortunately it is harder to write and harder to maintain meson.build than Makefile for pgxs
I am not sure if there are some authorities who specified some generic template of meson.build for extensions.
Maybe with some Postgres Meson's extension for building postgres's extension then writing meson.build can be more easy than it is now - but now, there is zero support for meson for extension from Postgres side.
