[Bug #548] segmentetion fault by socket connection

e$B%A%1%C%He(B #548 e$B$,99?7$5$l$^$7$?!#e(B (by Yukihiro M.)

e$B$&$A$G$O:F8=$7$^$;$s$M!#F1$8e(Bi686-linuxe$B$J$N$K!#e(B
-ve$B$N=PNOe(Brevision 18218e$B$O$+$J$j8E$$$G$9$,!“$3$l$OC1$Ke(Bmake
upe$B$7$F$$$J$$$@$1$G$7$g$&$+!#e(Btrunke$B:G?7$G$9$+!)e(B
e$B$^$?!”<B9T$Oe(Bmake installe$B$7$?>uBV$G9T$C$F$$$^$9$+!)e(B

http://redmine.ruby-lang.org/issues/show/548