* New builtin function "isFunction". You're not supposed to use it

;-)
* Channels: fix channels that are plain lists of derivations (like
  strategoxt-unstable) instead  of functions (like nixpkgs-unstable).
  This fixes the error message "error: the left-hand side of the
  function call is neither a function nor a primop (built-in
  operation) but a list".

corepkgs/channels/unpack.sh.in

@@ -24,7 +24,7 @@ for ((n = 0; n < ${#inputs[*]}; n += 2)); do
     @coreutils@/mv * ../$dirName # !!! hacky
     
     attrName=$(echo $dirName | @tr@ -- '- ' '__')
-    echo "$attrName = import ./$dirName {};" >> $expr
+    echo "$attrName = let e = import ./$dirName; in if builtins.isFunction e then e {} else e;" >> $expr
 done
 
 echo '} // {_combineChannels = true;}' >> $expr