dub segfault

[Joe]

I'm getting a segmentation fault when I run 'dub build' and I 
specify a dependency. Specifically, the dependency is 
'derelict-pq' but it could be anything (I tried 'dpq2' and even 
'mysql-native', just for kicks). The segfault occurs when it's 
supposedly searching for the dependency.  Here's the partial 
output of 'dub --vverbose build'

Collecting dependencies for select
   Version selection for dependency derelict-pq (derelict-pq) of 
select is missing.
   Missing dependency derelict-pq >=3.0.0-beta.3 <3.1.0-0 of select
Checking for missing dependencies.
Search for versions of derelict-pq (1 package suppliers)
Segmentation fault

The dub.json is trivial and works to properly build a program 
with 'libpq' directly.  And two months ago I had built the 
derelict-pq sample program and AFAIR everything went fine.

When this first happened last night, code.dlang.org was 
temporarily not accessible but that's been resolved now.  Before 
I report this as an issue, I thought I'd get some feedback.  I'm 
running dub 1.7.0-2, built on Jan  3 2018, on Debian buster.