sed: avoid MSVC build failure

* sed/sed.c (usage): Remove unnecessary forward declaration.
Reported by Bruno Haible in
https://lists.gnu.org/r/sed-devel/2020-01/msg00007.html

1 files changed, 0 insertions, 1 deletions

diff --git a/sed/sed.c b/sed/sed.c
index df88b2a..f75e4b6 100644
--- a/sed/sed.c
+++ b/sed/sed.c
@@ -117,7 +117,6 @@ cancel_cleanup (void)
   G_file_to_unlink = NULL;
 }
 
-static void usage (int);
 static void
 contact (int errmsg)
 {