- Use mmap via the configure argument instead of hard-coding it. - Define USE_MMAP_ANON for OpenBSD when --enable-mmap is configured - Remove unused ELF_CLASS define for OpenBSD. - Remove old HAVE_DL_ITERATE_PHDR workaround for OpenBSD. - Don't use old GC_find_limit_openbsd() which is only needed for uthreads. Tested on i386/amd64/sparc64/aarch64/powerpc/powerpc64/mips64 okay sthen@, gkoehler@