[gentoo-user] why both /usr/lib and /usr/lib64 on a 64bit system?

[Valmor F. de Almeida]

Hello,
I use the global flags USE="elogind alsa -multilib -abi_x86_32" and I 
thought this would prevent 32bit libraries to be installed.

For example I have (from glibc) both:

/usr/lib/libutil.so
/usr/lib64/libutil.so

this causes problems with some packages outside portage that I would 
like to install. The install fails (or is incomplete) because it is 
trying to link a 32bit incompatible library, e.g.:

/usr/lib/gcc/x86_64-pc-linux-gnu/9.3.0/../../../../x86_64-pc-linux-gnu/bin/ld: 
skipping incompatible /usr/lib/libutil.so when searching for -lutil

Is there a way to have only /usr/lib64 in gentoo or is this not 
possible? I do use

export LD_LIBRARY_PATH=/usr/lib64:$LD_LIBRARY_PATH

in my shell startup file.

Thanks for inputs.
--
Valmor