by Ostsol:

What steps will reproduce the problem?

Remove void from the parameter list of the function definded on line 19 of 
$GOROOT/misc/cgo/stdio/file.go.  This changes the line to read:

void fflushstdout() { fflush(stdout); }

What is the expected output? What do you see instead?

cgo should recognise the empty parameter list, but instead reports a fatal 
error: 'unexpected type: ...'.

What is your $GOOS?  $GOARCH?

linux AMD64

Which revision are you sync'ed to?  (hg log -l 1)

changeset:   4018:bbc290c53f85
tag:         tip
user:        Kai Backman <kaib@golang.org>
date:        Thu Nov 12 16:12:28 2009 -0800
summary:     fix style nit ignored in previous cl