The build of 32 bit Windows is broken because of mlib_image.dll. As JNICALL modifier has been added to function declarations, they're exported with a decorated name, for example _j2d_mlib_ImageCreate@16. The functions in this library are looked up by their name [1] and therefore none can be found.
If you run tests in test/jdk/java/awt/image, for example test/jdk/java/awt/image/mlib/MlibOpsTest.java, some of them fail because ImagingLib is not available.
This is a follow-up for JDK-8201226,
http://mail.openjdk.java.net/pipermail/2d-dev/2018-April/009150.html
[1] http://hg.openjdk.java.net/jdk/jdk/file/bc1c7e41e285/src/java.desktop/windows/native/libawt/windows/awt_Mlib.cpp#l60