Unknown open() mode '<:utf8'

[u8526505]

I was using a limited Perl5.6 on an embedded Linux system. When I try
to use 'open A,"<:utf8",'file'' to open a file in utf8 mode, I got this
error - Unknown open() mode '<:utf8'. Is this because the Perl build I
used does not support utf8? If so, what modules should I add to make it
work?
I've tried to build Perl5.8 on that platform for a better Unicode
support but the build script got segmentation fault while creating
Config.pm. That's another story anyway...

Thanks.