Cross-compiling ruby-1.8.6-p368 to bfin-uclinux in CentOS 5.2

hi,

( after reading
http://groups.google.fr/group/comp.lang.ruby/browse_thread/thread/01b329d581fd1944
)
I tried to compile ruby-1.8.6-p368 for bfin-uclinux , but i got an
Erreur:

/usr/bfin-uclinux/ruby/ruby-1.8.6-p368/ruby.c:196: undefined reference
to `_mblen’
collect2: ld returned 1 exit status
make[1]: *** [ruby] Erreur 1

Thanks