#option platform cygwin|mingw|mswin
#option nodynamic
bigdecimal
cgi/escape
digest
digest/md5
digest/rmd160
digest/sha1
digest/sha2
etc
fcntl
#io/wait
nkf
#openssl
#pty
#racc/cparse
#readline
#ripper
socket
stringio
strscan
#syslog
win32ole
#zlib