alpha amr tip

Originally committed as revision 2683 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -1259,6 +1259,7 @@ else
   echo "REL-5 V5.1.0 from "
   echo "http://www.3gpp.org/ftp/Specs/latest/Rel-5/26_series/26104-510.zip"
   echo "and extracted the source to libavcodec/amr_float"
+  echo "and if u try this on an alpha, u may need to change Word32 to int in amr/typedef.h"
   echo
 fi