Karl:

>  The first one gives me an unbootable system
> $ ldd /sbin/init | grep /usr
>         libpcre2-8.so.0 => /usr/lib/x86_64-linux-gnu/libpcre2-8.so.0 (0x00007f737ba28000)

...

So, how do I change the above package to install the lib in
/lib//x86_64-linux-gnu instead ?

I can get the source with:
$ apt-get source libpcre2-8-0
$ cd pcre2-10.36/debian

is it sufficient to change this file ?
$ cat libpcre2-8-0.install
debian/tmp/usr/lib/*/libpcre2-8.so.*
$

and if I manage to create the package, what name should I give it,
something like libpcre2-8-0_nonusrmerge or what ?

Regards,
/Karl Hammar