in make/bsd/makefiles/gcc.make the variable to specify warnings flags is incorrectly named. This results in the flag not being used in the build.

- WARNINGS_FLAGS += -Wconversion
+ WARNING_FLAGS += -Wconversion

Unfortunately enabling this flag causes compilation failure in hotspot/src/share/vm/gc_interface/collectedHeap.inline.hpp during generation of precompiled headers due to warnings being treated as errors. There are possibly other problematic files.