My solution for C software that I maintain is handwritten ./configure of 200-ish lines of code, dealing with specific issues that I've encountered, supporting s

My solution for C software that I maintain is handwritten ./configure of 200-ish lines of code, dealing with specific issues that I've encountered, supporting specific systems that are supported (Linux, macOS, Emscripten, MinGW). It looks and feels like Autotools script, outputs a file for make to include later, etc. If you're a user, familiar ./configure && make && sudo make install will do the trick for you. If you're a package maintainer, ./configure supports all the --libdir flags that packaging system sets, (handwritten) Makefile respects CFLAGS, DESTDIR, etc. All of it is extremely hackable since there are no silly layers of preprocessors between you and make. I guess the secret sauce here is having only OpenSSL as a dependency and the project being a fairly small library.