How to best handle ports mislinking against locally installed copies?

[Edward Sanford Sutton, III]

As an example, net/avahi-app fails to build on my machine because of the 
error:
/libexec/ld-elf.so.1: Shared object "libicui18n.so.38" not found, required 
by "libavahi-glib.so.1"
This can be fixed by removing the port before building so that it is unable to 
link against /usr/local/lib/libavahi-glib.so.1 and instead correctly links 
against ./work/avahi-0.6.29/avahi-glib/.libs/libavahi-glib.so.1 but is it 
correct to assume uninstall is needed before attempting to build a new 
version or are there suggested fixes or examples of working through this?
I can try to dig up other examples I have ran into in detail but was wondering 
about the general approach and if the freebsd ports tree likes to fix it, 
note it, or ignore it?
Thanks again,
Edward Sanford Sutton, III