When you think about GNU autotools they're all about being able to compile on platforms that the software has never been compiled on before - that's why there are all those feature tests to see what the OS and compiler support.

I've done this many times on things like AIX 4.3 and HP-UX and so on. Sometimes you can get through the compile without any problems at all and the tool often works enough for your usecase and that's a win.

Sometimes there are particular little problems, sometimes it's something serious like an actual missing C library call or whatever and then you have to do some work. With nicely designed tools that have fairly wide support to begin with this tends to be easier.