i think that most target tuples that `config.guess' generates have the OS version included. certainly i can't think of anything except linux that doesn't :-)
As you can see, different output by different config.guess scripts. Also notable, the config string doesn't tell you I'm running an ELF system (for i386 it is i386-netbsdelf1.5 or even i386-netbsdelf1.5.3, apparently), but it really is ELF: (real)~$ file $(which file) /usr/bin/file: ELF 64-bit LSB executable, Alpha (unofficial), version 1, dynamically linked (uses shared libs), stripped This is a comment in one of the config.guess scripts: # The Operating System including object format, if it has switched # to ELF recently, or will in the future. conclusion: Big Mess(tm). =) FWIW, we (netbsd) plan on removing the 'elf' part 2 major releases after the port went ELF. eg, for i386 & sparc that will be after the next release, as they both were ELF first in the current release. other ports (such as the m68k, vax and sh) haven't yet switched in a release (though most will be for the next release) and others (like powerpc, mips and alpha) have been ELF for several releases. .mrg.