The history of how paths work in Win32 is a sad story and shall not be documented here.
Needless to say, Windows hates the temporary file name for jansi's native code since it
includes the version. For git builds, it includes quotes around the actual version. But
alas, the issue apparently doesn't occur if you build on Windows since it removes the
quotes from the git commandline that is ultimately used to build the version string,
because of more Win32 sadness and shame.
Go look at Raymond Chen's blog, The Old New Thing. It's full of Windows oddities and
it will make you want to weep because almost 90% of the world uses this legacy OS from
the 1980s.
Andrew Steinborn