Then make fails on:
In file included from /boot/home/yasm-0.7.0/modules/arch/x86/x86cpu.gperf:30: /boot/develop/headers/posix/ctype.h:53: warning: `toascii' redefined /boot/home/yasm-0.7.0/util.h:120: warning: this is the location of the previousdefinition
Comment out lines 120-122 in util.h and retry: ./configure
Then it builds without any problems.
Need to create a proper fix for this. It appears that yasm has moved the toascii from util.h to errwarn.c, so need to see how this affects things on svn trunk.