Configure error for www/node on rpi3 running -current

[bob prohaska]

Attempts to compile www/node on an rpi3 running -current at r349989 with
ports at 506782 reports:

....
File "tools/gyp/pylib/gyp/generator/make.py", line 1756, in WriteMakeRule
    cmddigest = hashlib.sha1(command if command else self.target).hexdigest()
AttributeError: 'module' object has no attribute 'sha1'
===>  Script "configure" failed unexpectedly.
Please report the problem to bhughes at FreeBSD.org [maintainer] and attach the
"/usr/ports/www/node/work/node-v12.6.0/config.log" including the output of
the failure of your make command.
....

However, the log file requested doesn't seem to exist. The last successful
build of www/node was 12.1, now it's up to 12.6.

Thanks for reading, any suggestions appreciated,

bob prohaska