Print out more verbose licensing information.

Originally committed as revision 18893 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -2383,11 +2383,11 @@ for type in decoder encoder hwaccel parser demuxer muxer protocol filter bsf ind
     echo
 done
 
-license="LGPL"
+license="LGPL version 2.1 or later"
 if enabled nonfree; then
-    license="unredistributable"
+    license="nonfree and unredistributable"
 elif enabled gpl; then
-    license="GPL"
+    license="GPL version 2 or later"
 fi
 
 echo "License: $license"