Hello, In OpenBSD (built just with gcc) the "stdint.h" -> "inttypes.h" patch was also required (see Oliver Braun's earlier advice for compiling on Solaris). The whole thing stopped with: nhc/nhc98-1.12/targets/ix86-OpenBSD/obj/hattools/HatObserve.o HatObserve.hs cd /q/pd/nhc/nhc98-1.12/targets/ix86-OpenBSD/obj/hattools && /q/pd/nhc/nhc98-1.12/script/nhc98 +RTS -K10M -RTS +CTS -H20M -CTS -o HatObserve Run.o PrettyLibHighlight.o HighlightStyle.o PrettyExp.o HatExpressionTree.o HatTrie.o HatTrace.o HatObserve.o /q/pd/nhc/nhc98-1.12/targets/ix86-OpenBSD/obj/hattools/hatlib.a observe.c:604: Undefined symbol `_newFunTable' referenced from text segment observe.c:616: Undefined symbol `_addToFunTable' referenced from text segment observe.c:624: Undefined symbol `_FunTableCheckArities' referenced from text segment collect2: ld returned 1 exit status I find this a little worrying. The previous two versions of nhc were quite painless to build on all sorts of systems, including Solaris and OpenBSD: this is not an advantage that should be given up easily! Regards, -- Feliks