make JAVAC_OPTIONS configurable
# javac runs out memory on Mac so increase heapsize if(APPLE) set(JAVAC_OPTIONS -J-Xmx512m) endif()
Now, that's a bit arbitrary. Why only on
512m? In fact, on Debian we had to increase this to
1024m, see https://anonscm.debian.org/cgit/debian-science/packages/vtk6.git/tree/debian/patches/100_javac-heap.patch.
It'd suggest to make this configurable, perhaps via