1.0.46.22: fix sb-posix readdir on SunOS/x86

1.0.46.22: fix sb-posix readdir on SunOS/x86

 for the time being, disable :largefile on SunOS/x86.  Unfortunately,
 sb-grovel cannot navigate the somewhat sticky way in which struct
 dirent gets setup for a 32-bit host with 64-bit ino_t on SunOS, so
 sb-posix:readdir breaks

 :largefile works fine on SunOS x86_64, and will be re-enabled on x86
 after I get some more time to fight with the alien def for struct dirent