Shared libs with version numbers.

Silly question since I work with aix and it doesn't appear to use
the version numbers for shared libs...

Is there any purpose to the version numbers that some ports append
to a shared lib name, besides keeping different versions around?

I've managed to move the port specific code from all of the various
interfaces that make shared libs, but I'd like to understand the
rhyme/reason before I post a patch that breaks all other ports.

Using libpq as an example, is there a difference to the system if...

$(MAKE) libpq.so
$(INSTALL) libpq.so libpq.so.1
$(LN) libpq.so.1 libpq.so

...rather than...

$(MAKE) libpq.so.1
$(INSTALL) libpq.so.1 libpq.so.1
$(LN) libpq.so.1 libpq.so

???

If no difference to the system, the former is _much_ easier to add
shared lib support for aix and use the %.$(DLSUFFIX) rules in the
port Makefiles.

This would be perhaps the final step to removing $(PORTNAME) from the
code, these Makefiles would not have to be generated by configure, and
makes the interfaces/* Makefiles much cleaner.

darrenk