Linking problem

[Bruce Labitt]

Puzzling over the use of ldconfig.  As I understand it ldconfig can be 
used to rebuild/locate all the shared libraries.  It looks in ld.so.conf 
for the directories to use. In my case ld.so.conf has one line in it:

"include /etc/ld.so.conf.d/*.conf"

I have 3 conf files in ld.so.conf.d.

libc.conf:

     /usr/local/lib

x86_64-linux-gnu.conf:

     /lib/x86_64-linux-gnu

     /usr/lib/x86_64-linux-gnu

i386-linux-gnu.conf:

     /lib/i386-linux-gnu

     /usr/lib/i386-linux-gnu

If I $ sudo rm /etc/ld.so.cache and $ sudo ldconfig -v, I get the message

     /sbin/ldconfig.real: Path `/lib/x86_64-linux-gnu' given more than once
     /sbin/ldconfig.real: Path `/usr/lib/x86_64-linux-gnu' given more 
than once

Why would this happen?  Is this ok?

I haven't gotten to my actual question yet, but this is puzzling me.  
Ubuntu 18.04 LTS, if this matters.  I'm trying to figure out if things 
are ok enough to ask why the linker can't find a file, even though I see 
it in ldconfig.  Maybe what I am asking is how to force a new 
configuration after deleting the ld.so.cache.