[FFmpeg-cvslog] version.sh: add a little usage comment

[Timothy Gu]

ffmpeg | branch: master | Timothy Gu <timothygu99 at gmail.com> | Thu Nov 28 16:57:49 2013 -0800| [3c5c4cfa156c5991b3a0d3824be02208c82e0292] | committer: Michael Niedermayer

version.sh: add a little usage comment

Signed-off-by: Timothy Gu <timothygu99 at gmail.com>
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3c5c4cfa156c5991b3a0d3824be02208c82e0292
---

 version.sh |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/version.sh b/version.sh
index 62882e0..c28ffe7 100755
--- a/version.sh
+++ b/version.sh
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+# Usage: version.sh <ffmpeg-root-dir> <output-version.h> <extra-version>
+
 # check for git short hash
 if ! test "$revision"; then
     revision=$(cd "$1" && git describe --tags --match N 2> /dev/null)