Dealing with a zillion of handwritten Makefiles sounds more hellish than dealing with autotools. These Makefiles will be more fickle, too. I'm not seeing a convenience win.
I'm sure part of the problem is I don't understand autotools as well as I could. But when "build expertise in autotools" is on the table, stabbing my eyes out with a fork starts to seem like an appealing option.
Suffice it to say, I prefer to work with handwritten makefiles.
After working on many different software libraries and frameworks, my firm belief is that you really need to understand the lower layers to use and troubleshoot them effectively.
Best case scenario there are excellent error messages and you can easily review logfiles to understand the root cause of the problem.
But that is rarely the case. Instead you have to have a detailed mental model of the library/framework you're using, and you must be able to quickly picture what it will do internally for the inputs that you give it.
Once you get to that point, many bugs don't appear in the first place because you immediately see that the input/usage doesn't make sense. And the bugs that do happen become much easier to figure out from the output and cryptic error messages you get.
All this to say that it is really unappealing to work on things like bugs in someone else's autotool scripts. I just want to compile the program to run it. I don't want to spend months of my life to understand the inner workings of autotools.
Compare it to CMake or even cargo - which fundamentally solves the same problem, faster and more reliably on more operating systems. And for no cost at all. The opposite: it’s easier to configure and use.
Makefiles can be quite elegant. But it really seems like a waste of human potential to put up with such crap software as autotools. How many neurons do you have devoted to it? You could have used the same time and effort learning something that matters or that brings you joy.
CMake based compilation breaks far more often for me than with Autotools and because of the crappy documentation I can rarely fix it myself.
Cargo and other modern package manager OTOH are bliss compared to both CMake and Autotools but they are usually language specific and other modern non language specific build system are still leading a niche existence.
I hear you about CMake.
I think what kills me about all of this stuff is that there's no essential reason we can't have something as nice as cargo for C and C++ code. Compiling C isn't a fundamentally more complex problem than compiling rust or swift. But instead of solving the problem in a clean, generic, cross-platform way that understands package interfaces and boundaries, C/C++ instead accreted hacky, vendor specific macros and junk for decades. And then C build tools need to be horribly complicated to undo all of that damage.
Should your code export functions with __declspec(dllexport) (as VC++ demands) or __attribute((dllexport)) for gcc. Can't choose? Maybe your library should define its own idiosyncratic DLL_PUBLIC macro which looks at whether _WIN32 or __GNUC__ is defined on the platform. And now the header file (and thus the exposed functions) can only be machine interpreted if you know which platform / compiler you're building for. What does it do for clang? What should clang do? Aaahhhh nightmare o'clock.
All of that when C could just do what every other modern language does and have a nice machine readable public attribute, that gets interpreted differently based on whether the code is compiled into a dynamically linked library or compiled statically. I know hindsight is 20/20. And I'm hopeful that C++20's modules will eventually help. But there's so much stuff like this to unpick that it'll take decades, if it happens at all.
We can have nice things. It just takes some engineering and a willingness to change.
I'm sure I'm missing something, and it's possible that they don't scale well, but I prefer it to any other could system for small C projects.
That said, autotools, with its multiple layers of file generation, makes debugging rather annoying. And it's generally much easier to fix a broken Makefile than figuring out why autotools goes wrong.
Assuming you can ignore Windows you'd typically end up with two makefiles (Makefile and GNUMakefile) and a bunch of includes sharing code all make variants understand.