Hello, By examining the code in both /usr/local/include/gc.h and libguile/pairs.h I managed to resolve the problems. I did this by adding two lines to gc.h, at the top of the file. #define HAVE_GC_IS_HEAP_PTR              // OSJ #define HAVE_GC_MOVE_DISAPPEARING_LINK   // OSJ This is maybe not your preffered solution, but I managed to compile and link the libraries and programs. Hopefully this helps you. Best regards, -- Sören Jonsson Kärnvägen 237 906 27 UMEÅ SWEDEN Tel: 090-180 339, 070-603 3896