windows cfbot failing: my_perl

The last 20 some consecutive builds failed:
https://cirrus-ci.com/github/postgresql-cfbot/postgresql

like this:
[09:29:27.711] C:\Program Files (x86)\Windows Kits\10\Include\10.0.20348.0\ucrt\malloc.h(159,17): error C2065:
'my_perl':undeclared identifier (compiling source file src/pl/plperl/SPI.c) [c:\cirrus\plperl.vcxproj]
 
[09:29:27.711] C:\Program Files (x86)\Windows Kits\10\Include\10.0.20348.0\ucrt\malloc.h(159,17): error C2065:
'my_perl':undeclared identifier (compiling source file src/pl/plperl/Util.c) [c:\cirrus\plperl.vcxproj]
 
[09:29:27.711] C:\Program Files (x86)\Windows Kits\10\Include\10.0.20348.0\ucrt\malloc.h(159,17): error C2223: left of
'->IMem'must point to struct/union (compiling source file src/pl/plperl/SPI.c) [c:\cirrus\plperl.vcxproj]
 
[09:29:27.711] C:\Program Files (x86)\Windows Kits\10\Include\10.0.20348.0\ucrt\malloc.h(159,17): error C2223: left of
'->IMem'must point to struct/union (compiling source file src/pl/plperl/Util.c) [c:\cirrus\plperl.vcxproj]
 

I imagine it may be due to an error hit while rebuilding the ci's docker image.

-- 
Justin