[rleigh]

There are likely to be some, but they will be a minority. And just like open source projects, their number will be dwindling. In both arenas, I've encountered CMake more than anything else over the course of the last decade.

You're absolutely correct that Autotools is no longer synonymous with portability. If it ever was. Not catering for Windows or iOS means it's missing out on the lion's share of the market. There's a massive misplaced priority in catering for 90s Unix platforms which have marginal use by hobbyists and zero commercial use, above current open source and proprietary platforms. And this doesn't just extend to operating systems, it also extends to language support. C++17, C++20, Rust, Go, Swift, you name it. It's not kept up. Likewise build systems. It's make-only. And what about language and platform feature tests and support for stuff like threading, locking etc. It's non existent other than some third-party support which is quite limited.

It's for all these reasons, as well as other well documented problems, that I moved all my personal projects over to CMake, as well as work projects, and other open source projects. I needed to support Windows. I needed to support building libraries on multiple platforms. I needed threading support. I needed C++14, and C++17 support.

For some open source projects I maintain both Autotools and CMake support. I've had several instances of people trying to build on e.g. Solaris and having problems. I always ask "Were you using the Autotools build, or CMake?" They tell me they used the Autotools and I suggest retrying with CMake. It always works. In short: portability to other Unix systems is inferior today compared with CMake. That's supposed to be its main advantage...

Agreed about the shell. There is no point to M4 and it could be removed compatibly by replacement with shell functions. This was true a decade ago. It was even true two decades ago.

With regards to migration. The time, money and effort required to upgrade the Autotools would be better spent on converting the affected project(s) to use CMake or some other more modern build tool. The functionality gap is simply too big to overcome at this point, and the contributor base for CMake is large. The FSF have only themselves to blame for their contribution and development practices hindering forward progress, as well as a lack of concern for the real-world needs for software development. The turnaround time for submitting a CMake change is a few days to get it change reviewed and integrated, and a few weeks to be in a release.

I've converted some large and complex projects to use CMake over the years, including Xerces-C, Xalan-C, libtiff and others. All in all, that time was well spent, and I'd rather have done this than waste time updating Autoconf/make/libtool.

Regarding Debian. Current unstable Build-Depends is 1999 (CMake), 1544 (Autotools), 395 (Meson). So I think we're a good way past the tipping point now.

Full disclosure: I've done the FSF copyright assignment for Autoconf and Automake and submitted some major features like C99 support. I'm also a CMake maintainer and I've submitted many different changes there. Primarily lots of Find module support including the Boost support, but also some lower-level bits and pieces as well. The community surrounding CMake is very active and also very friendly to submissions from new people. Kitware really deserve appreciation and thanks for their fostering and growing the community and committing resources to it including timely and friendly code review.

[jwilk]

> Current unstable Build-Depends is 1999 (CMake), 1544 (Autotools), 395 (Meson)

These days pretty much everything build-depends indirectly on autotools, via debhelper → dh-autoreconf → autoconf.

These numbers are probably more meaningful:

  $ wget -q https://deb.debian.org/debian/dists/unstable/main/Contents-source.gz

  $ zgrep -E $'(^|/)configure[.](in|ac)\t' Contents-source.gz | cut -f 2 | tr ',' '\n' | sort -u | wc -l
  5562

  $ zgrep -E $'(^|/)CMakeLists[.]txt\t' Contents-source.gz | cut -f 2 | tr ',' '\n' | sort -u | wc -l
  2455

  $ zgrep -E $'(^|/)meson[.]build\t' Contents-source.gz | cut -f 2 | tr ',' '\n' | sort -u | wc -l
  466

[bonzini]

> There is no point to M4 and it could be removed compatibly by replacement with shell functions.

Autoconf has been using shell functions since 2008 (support added by me :)). M4 is used to properly handle dependencies between tests and to store information that is used later when generating files.

[nwellnhof]

> In short: portability to other Unix systems is inferior today compared with CMake.

CMake requires a C++11 compiler and quite a few C libraries like libuv, so you can't even compile it on platforms like HP-UX.

[mathstuf]

Brad has submitted generic POSIX support to libuv for fallback support (I forget which platforms exactly were in consideration at the time). We even have a tracking issue for HP-UX support which tracks the status:

https://gitlab.kitware.com/cmake/cmake/-/issues/17137

Part of it is HP saying they'd have a C++11 compiler and then not, some is modern GCC being a problem to compile as well.

C++11 and libuv have vastly improved the situation in CMake's codebase itself and letting HPE hold everyone else hostage for that would not have been worth it (and it takes a lot for us to drop platforms). IRIX was dropped because its owner killed it off and we're looking at dropping support for macOS 10.9 and older (in premade binaries; feel free to compile yourself) because we don't actually have tests running on those older releases.

https://gitlab.kitware.com/cmake/cmake/-/issues/20825

Full disclosure: CMake developer here.

[jnxx]

> primarily lots of Find module support including the Boost support, but also some lower-level bits and pieces as well.

Last time I checked, the CMake docs say that adding find module support is responsibility of the user. Which is a main reason why pkgconf-based dependency resolution works much better with other build systems. If you compile package abc on, say, Ubuntu, and it needs package xyz you do not need to bother about how it is found. You just install xyz.

What I want to say, CMake makes things way more complex and solves problems which exist only on Windows. Otherwise, it does not add much, and is a burden. Why should developers on Linux carry that burden?

[jnxx]

> Not catering for Windows or iOS means it's missing out on the lion's share of the market.

Do you mean the market for free software?

I guess the GNU/Linux developers are not that keen to work for free to support commercial, nonfree platforms.....

[rleigh]

Most of the GNU software catalogue has historically been supported on nonfree platforms. Nothing to do with Linux here, it's not part of the equation.

None of this consideration is really concerning free software or proprietary software specifically. It's simply looking at cross-platform capability. If you need to develop cross-platform software of either sort, it's not typical to be able to ignore Windows. It's ~90% of the market. Similar considerations for other markets like smartphones.

None of that is reflective of my personal preferences, simply stating the requirements which drive the build system considerations of many projects. The GNU Autotools are unsuitable for the vast majority of current systems in existence, and that means selecting it for its portability is nowadays often not a possibility because their choice to not support common platforms makes it untenable.

[Nemo_bis]

This is like complaining that the supply chain of oat milk is incompatible with 90 % of the systems that produce (cow-based) butter. We don't necessarily care.

[jnxx]

> And this doesn't just extend to operating systems, it also extends to language support. C++17, C++20, Rust, Go, Swift, you name it. It's not kept up.

Guix does support, for example, Rust and other languages relevant for Linux pretty well, and in a much better defined way than CMake.