forgot -ldl

git-svn-id: http://svn.xiph.org/trunk/ao@1024 0101bb08-14d6-0310-b084-bc0e0c8e3800

ao.m4

@@ -18,7 +18,7 @@ AC_ARG_ENABLE(aotest, [  --disable-aotest       Do not try to compile and run a
     AO_LIBS="-L$ao_prefix/lib"
   fi
 
-  AO_LIBS="$AO_LIBS -lao"
+  AO_LIBS="$AO_LIBS -lao -ldl"
 
   AC_MSG_CHECKING(for ao)
   no_ao=""