The libjsig library doesn't seem to work properly when only using DYLD_INSERT_LIBRARIES and DYLD_FORCE_FLAT_NAMESPACE on MacOSX. It seems to require DYLD_INTERPOSE.

This was discovered when altering the test open/test/hotspot/jtreg/runtime/signal/SigTestDriver.java for JDK-8345782. Without using DYLD_INTERPOSE the overriding signal() nor sigaction() is called.