32-bit glibc required in mock for building oorexx on x86_64. How?

[Gérard Milmeister <gemi bluewin ch>]

I imported the oorexx package into CVS Extras. It build fine on i386 and
ppc. However it requires the 32-bit glibc for building x86_64. Is there
a way to do this? When building in mock, only the the 64-bit library is
installed. I tried to require /usr/include/gnu/stubs-32.h explicitly,
but this didn't work.
-- 
Gérard Milmeister
Langackerstrasse 49
CH-8057 Zürich