Jom just stops while building Qt5.5

I downloaded and unzipped the Qt5.5 sources and configured with the following options:

configure -opensource -debug-and-release -opengl desktop -nomake examples -nomake tests -confirm-license -skip qtdoc -skip qtwebengine

I then started jom (tried 1.0.14 and 1.0.16) from a VS2013 x64 command prompt, which builds fine for a while but then simply stops. It looks like it has finished but quite a lot of modules haven't been built (no trace of multimedia or webkit to name only those). No errors are visible in the window.