Trying scons on a freshly darcs'd yhc from today, I got an error, see: http://paste.lisp.org/display/22129 or, to include the relevant parts of the output here: gcc -I. -c -o src/runtime/BCKernel/external.o src/runtime/BCKernel/external.c In file included from src/runtime/BCKernel/types.h:5, from src/runtime/BCKernel/hashtable.h:4, from src/runtime/BCKernel/module.h:18, from src/runtime/BCKernel/external.h:4, from src/runtime/BCKernel/external.c:1: src/runtime/BCKernel/platform.h:103:17: ffi.h: No such file or directory scons: *** [src/runtime/BCKernel/external.o] Error 1 scons: building terminated because of errors. On IRC, ndm suggested that "libffi" was needed; after "emerge libffi" the error still happened -- so, me being on gentoo-linux ppc, ndm on Windows, referred me to this list. I'm trying to find out what is actually needed to successfully compile Yhc (now, for me, at least).