BUG #16737: error running compiled C program with connection to Postgres

The following bug has been logged on the website:

Bug reference:      16737
Logged by:          richard bee
Email address:      rb9999999@gmail.com
PostgreSQL version: 13.1
Operating system:   Mac iOS Big Sur
Description:

This is an issue for both Apple and Postgres - I have registered the same
issue with Apple here:
https://feedbackassistant.apple.com/feedback/8907834

when running a compiled C program with connection attributes to postgres, I
now get the following error after upgrading to Big Sur:

dyld: Library not loaded: /usr/lib/libpq.5.dylib 
Referenced from: /xxdir/program
  Reason: image not found
Abort trap: 6

indeed, there is nothing in /usr/lib directory that resembles
libpq.5.dylib,
neither file nor link

and the /usr/lib directory in Big Sur is locked down and so cannot enter
anything here

have implemented the following without resolution:
https://stackoverflow.com/questions/64256675/copy-libpq-5-dylib-to-usr-lib-libpq-5-dylib

The code itself is the usual example of C to Progress connection code and
worked prior to Big Sur upgrade on my macbook pro 2018
sample c program to compile is here:
https://www.postgresql.org/docs/9.1/libpq-example.html

compilation command being used is:
gcc -o e1_ e1.c -I "/Library/PostgreSQL/13/include" -lpq -std=c99

The same error also happens with the clang compiler