buildbot exception in MacPorts on ports-10.15_x86_64-watcher

[buildbot at macports.org]

The Buildbot has detected a build exception on builder ports-10.15_x86_64-watcher while building MacPorts. Full details are available at:
    https://build.macports.org/builders/ports-10.15_x86_64-watcher/builds/11213

Buildbot URL: https://build.macports.org/

Buildslave for this Build: ports-10.15_x86_64

Build Reason: A build was forced by 'jmr <jmr at localhost>': force build
Build Source Stamp: HEAD
Blamelist: 

BUILD FAILED: exception

Sincerely,
 -The Buildbot