It takes about 5 minutes to make a nix expression for a "./configure && make && make install", with most of that time being figuring out the dependencies and calculating the checksum of the tarball.
For any standard build tools (cmake, scons, whatever) it's just one extra line. Applying patches is one extra line. For a non-standard workflow, you can supply a shell script for each step (unpack, configure, build, install, &c.). so it's just however many lines that is.
I've had zero issue getting any source-based third party stuff running. Binaries are a pain, but that's always true if you aren't running the exact distro that the binary was built for.
Example:
https://nixos.org/nix/manual/#ex-hello-nix
For any standard build tools (cmake, scons, whatever) it's just one extra line. Applying patches is one extra line. For a non-standard workflow, you can supply a shell script for each step (unpack, configure, build, install, &c.). so it's just however many lines that is.
I've had zero issue getting any source-based third party stuff running. Binaries are a pain, but that's always true if you aren't running the exact distro that the binary was built for.