As can be seen in the buildd report http://buildd.debian.org/build.php?&pkg=mlton&ver=20050901-1&arch=sparc&stamp=1126024698&file=log&as=raw -mv8 is no longer supported. Gcc 3.[23] and 4.0 both support -mcpu=v8, so use that instead. Sorry for not noticing this earlier, but I build mlton with 3.3. -- Wesley W. Terpstra