Link _fileio statically -- it is needed during initialization.

Modules/Setup.dist

@@ -115,6 +115,7 @@ pwd pwdmodule.c			# this is needed to find out the user's home dir
 				# if $HOME is not set
 _sre _sre.c			# Fredrik Lundh's new regular expressions
 _codecs _codecsmodule.c		# access to the builtin codecs and codec registry
+_fileio _fileio.c		# Standard I/O baseline
 
 # The zipimport module is always imported at startup. Having it as a
 # builtin module avoids some bootstrapping problems and reduces overhead.