Add an empty line in front of configure debug instructions.

This makes the actual error message that configure prints be more noticeable.

Originally committed as revision 18308 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -241,6 +241,7 @@ echolog(){
 die(){
     echolog "$@"
     cat <<EOF
+
 If you think configure made a mistake, make sure you are using the latest
 version from SVN.  If the latest version fails, report the problem to the
 ffmpeg-user@mplayerhq.hu mailing list or IRC #ffmpeg on irc.freenode.net.