In CoreLibraries.gmk we have

$(eval $(call SetupJdkLibrary, BUILD_LIBJIMAGE, \
...
   LIBS_unix := -ljvm -ldl $(LIBCXX), \
   LIBS_macosx := -lc++, \

I think the LIBS_macosx line should not be needed. Other similar places don't seem to do that. If it were necessary to explicitly add the C++ standard library to the link command, that would be better done by setting up LIBCXX.