The present databases/sqlite3-tcl port is built with MODTCL_VERSION = 
8.6, producing /usr/local/lib/tcl/sqlite3/libsqlite3513.so

I am working on a tcl9 application (given that the 8.6 series has had 
its final release), so wanted to use the tcl9 version of the sqlite3 
library and made a test port to suit. it seems libraries have been 
renamed in tcl9 to include the string 'tcl9' in the name, and the 
pkgIndex file handles this in cases that I have seen, but the tcl9 
version of libraries is not built by the present ports.

The build goes fine, the tcl9 library (libtcl9sqlite3513.so) is built 
and works in basic testing.

However, it conflicts with the sqlite3-tcl port due to having identical 
pkgIndex.tcl, manpage and example files.

My question is how this might be handled in the future, preserving the 
availability of the tcl8.6 version of the library for legacy applications.

- have two ports, sqlite3-tcl and sqlite3-tcl9 with CONFLICTS = 
    sqlite3-tcl-* ?
- two mutually-exclusive flavors of a single port ?
- or is there a way to have both installed at the same time, and 
overwrite the conflicting files on installation, which I guess breaks 
the convention to not touch files in another package?

Is there a precedent for this elsewhere? There are probably other ports 
like tcllib, tclthread that are currently not available for tcl9.

All advice, info welcome.

Chris