Add an alias for `which'.

--- abcde-2.3.99.6/abcde	2006-08-05 21:14:00.000000000 +0200
+++ abcde-2.3.99.6/abcde	2008-10-29 22:49:16.000000000 +0100
@@ -15,6 +15,11 @@
 
 VERSION='2.3.99-$Revision: 222M $'
 
+which ()
+{
+  type -P $1
+}
+
 usage ()
 {
 echo "This is abcde v$VERSION."