The guide for compiling OpenTTD for Linux, *bsd and other unix derivatives is kind of lackluster and messy.
Although it is entirely possible to compile it on a raspberry pi once you have the commands nailed down, it's gonna take some time to compile though (a few hours depending on existing CPU load, which seems to be the bottleneck on the 512MB model)
Here's a download link for a compiled dedicated server based on the 1.3.3 source, the executable is in the /bin directory in the openTTD folder:
http://filesmelt.com/dl/openttd-1.3_.3- ... d_.tar.bz2
Haven't tested it thoroughly but it works, even without the SDL libraries it would otherwise complain about.
But as said, the page for compiling it for anything *nix or alike REALLY needs a overhaul to both clean it up and making it more comprehensive and also easier to understand for someone new to compiling things themselves.
Especially considering ARM based hardware is on the rise and official precompiled packages targeting those platforms isn't being offered.
Although if adding ARM hardware to the compile farm it would probably be an idea to look at something like the
ODROID-U3 Community Edition IF it can be set to compile for older ARM architecture like the Raspberry pi's SoC.
Since then it'll both be much faster at compiling and also cover a broad range of ARM devices, except for the upcoming 64bit ones.