Build mod_perl and Perl with multiplicity, but without ithreads

I tried to build mod_perl with Perl configured without ithreads but with
enabled multiplicity option
(useithreads=undef, usemultiplicity=define) (-Duseshrplib enabled)
And I found that it's impossible to use multiplicity w/o threads in
mod_perl:

.....*warnings*.....
/mod_perl.src.dir/mod_perl.c:732: error: 'my_perl' undeclared (first use in
this function)
....*errors & warnings*......

Tell me please, is it reasonable behavior or it's mod_perl's bug?