Symbol map files are supported by several proprietary Unix toolchains, including Suns' and (iirc) HPs'. The syntax is nearly identical twixt Solaris and GNU (there's certainly a useful common subset iirc). The ELF symbol stuff is at least very very similar in concept. It might even be standardised, and/or tools may know the differing formats. Binary compatibility across different OSes tends not to be the most important of issues though..