ponyc -l fails to generate static library on windows

[ghost]

following along with https://bluishcoder.co.nz/2015/12/16/c-linkable-libraries-with-pony.html

I tried to compile the following on windows 10 with ponyc -l

actor@ Foo
  new create() =>
    None

  be hi() =>
    @printf[I32]("Hi\n".cstring())

And I get the following output:

C:\Users\jesse\source\ponytest>ponyc -l
Building builtin -> C:\Users\jesse\ponyc\packages\builtin
Building . -> C:\Users\jesse\source\ponytest
Generating
 Library reachability
 Selector painting
 Data prototypes
 Data types
 Function prototypes
 Functions
 Descriptors
Optimising
Writing .\ponytest.obj
Archiving .\ponytest.lib
The filename, directory name, or volume label syntax is incorrect.

C:\Users\jesse\source\ponytest>ponyc --version
0.19.0-35d7757 [release]
compiled with: llvm 3.9.1 -- msvc-14-x64

No object code or library archive are actually generated. Only ponytest.h.