dlsym opcode modified so that 0 for library is converted to RTLD_DEFAULT as the two don't match on Darwin. Made errno an opcode, as previous method depended on Linux internals. [1] https://opensource.apple.com/source/xnu/xnu-201/osfmk/libsa/errno.h.auto.html [2] https://pubs.opengroup.org/onlinepubs/9699919799/functions/errno.html Placed errno in internals and then alias inside posix vocabulary, as it seemed a waste to have another builtin stub for one symbol. Arguably maybe dlsym should be that way too, but leaving for now. Added OS make variable to conditionally set flags. Set stripping / minimization options based on it. Based off of https://github.com/flagxor/ueforth/pull/3 Thanks Ulrich!