Installing different PostgreSQL versions in parallel

Hi list

I'm in the course of creating PostgreSQL packages for Solaris. One of the
requirement is to install different PostgreSQL versions in parallel, the other
is to have all the libraries stuffed in one place.

Now, if I install, let's say, pgsql 8.3 and 8.4 in parallel and all libraries
go to /opt/csw/lib, I end up with:

$ ls -l /opt/csw/lib/libpq*
lrwxrwxrwx   1 root     root      libpq.so -> libpq.so.5.2
lrwxrwxrwx   1 root     root      libpq.so.5 -> libpq.so.5.2
-rwxr-xr-x   1 root     bin       libpq.so.5.1
-rwxr-xr-x   1 root     bin       libpq.so.5.2

Which in turn leads to 8.3 binaries loading libpq.so.5.2, effectively mixing
8.3 binaries with 8.4 libraries.

Finally, the question: How bad is it having a pgsql binary version X.Y using a
library X.Z?

Thanks for your help.

Cheers
Rafael