I would like to add options to the compile and link line used for building the threads library. I have added as follows but not sure if it's the proper place for it. With these changes, I'm able to cleanly compile and build the threads shared lib using aC++ 3.55 compiler. Credit to the HP aC++ team for their help on hpux.hpp changes. boost_1_31_0/tools/build/v1/acc-tools.jam:105 $(acc.bin-directory)$(CXX) -AA -mt +z -w -c +W823 -I$(BOOST_ROOT) -U$(UNDEFS) -D$(DEFINES) $(CFLAGS) $(C++FLAGS) -I"$(HDR S)" -I"$(STDHDRS)" -o "$(<)" "$(>)" boost_1_31_0/tools/build/v1/acc-tools.jam:82 $(acc.bin-directory)$(CXX) $(LINKFLAGS) -AA -mt -b -o "$(<[1])" -L$(LIBPATH) -L$(STDLIBPATH) "$(>)" "$(NEEDLIBS)" "$(NEEDLIBS)" -l$(FINDLIBS) boost_1_31_0/boost/config/platform/hpux.hpp:63 #define BOOST_HAS_PTHREADS -Jerry