Created attachment 15953 [details] 3.1.3 cygwin build log The previous verion 3.1.2 compiles ok nder Cygwin x64. The 3.1.3 gives following errors. Please disregard lines starting with "==" that are byproduct of Cygwin build script.
FYI, I checked out the git and it compiles ok. 2020-04-29 f7746d00 If you could release a new version, this bug can be marked resolved
Fixed in upcoming 3.2.0 release.