added libjansson-devel for building on win
Next, re-run cygwin's `setup-x86.exe` (or `setup-x86_64.exe` if you're using 64bit cygwin) with the following arguments,
which will install the packages required for building:
- setup-x86.exe --package-manager --wait --packages automake,pkg-config,make,gcc-core,libncurses-devel
+ setup-x86.exe --package-manager --wait --packages automake,pkg-config,make,gcc-core,libncurses-devel,libjansson-devel
Build as under Unix: