Isn't standardization a lovely thing. This morning, I thought I had a new rsyslog release ready. Then I did what was intended to be a quick test on FreeBSD. Guess what - nothing worked at all ;) The reason was that I made the makefile more user-friendly, enabling easier feature selection. For this, I needed to use make file conditionals. As it turned out, they are different between the standard make in Linux and that in FreeBSD. I guess I could have found a make tool for FreeBSD without these incompatibilites - but after all, I want to make it run as easy as possible, which means with as few prerequisites as possible.
I now have split the makefile into a common file and os-specific files in newly created os (or distro) subdirectories. I do not like this approach really much - but as far as I can see currently, it probably is the best. Eventually some Linux wizards will tell me a solution (or I will have a really bright idea), but for the time being, I will have to live with that.