Issues with MacPorts migration from 10.12.6 Sierra to 10.14.6 Mojave

[Greg Earle]

I recently replaced my Mac Pro's logic board which came with up-to-date 
firmware so now I'm on Mojave, finally.

I went through the MacPorts migration steps but am having loads of 
problems.

They started with the "./restore_ports.tcl myports.txt" step.  
Permissions errors (unable to create directories or symbolic links; even 
after running "port self update"), then spurious claims of "could not 
set effective uid to 504: 1 Operation not permitted".  I couldn't solve 
either of these issues.

Eventually I just took the list of previously-installed ports in 
"myports.txt" and tried to install them individually.

But I'm getting a ton of repeated errors like this one:

--
Error: Requested variants "" do not match those the build was started 
with: "+universal".
Error: Please use the same variants again, or run 'port clean expat' 
first to remove the existing partially completed build.
Error: See 
/opt/local/var/macports/logs/_private_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_textproc_expat/expat/main.log 
for details.
Error: Follow https://guide.macports.org/#project.tickets to report a 
bug.
Error: Processing of port fontconfig failed
--

Sometimes instead of "+universal" it's complaining about 
"+java+universal":

--
--->  Computing dependencies for p5.26-xml-sax-base
--->  Dependencies to be installed: perl5.26 db48 gdbm gettext libiconv 
ncurses readline
Error: Requested variants "" do not match those the build was started 
with: "+java+universal".
Error: Please use the same variants again, or run 'port clean db48' 
first to remove the existing partially completed build.
Error: See 
/opt/local/var/macports/logs/_private_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_databases_db48/db48/main.log 
for details.
Error: Follow https://guide.macports.org/#project.tickets to report a 
bug.
Error: Processing of port p5.26-xml-sax-base failed
--

All I'm doing is iterating over "port install <portname>", so I have no 
idea why it's claiming there was a previous "+universal" or 
"+java+universal" build.

All I know is that around half of the builds are failing with this 
issue.  Even though I did a "port -f uninstall installed" beforehand to 
start clean.

Any ideas?

		- Greg