+TF/02 Correct gecos expansion when From: is a prefix of the username.
+
+ Test 0254 submits a message to Exim with the header
+
+ Resent-From: f
+
+ When I ran the test suite under the user fanf2, Exim expanded
+ the header to contain my full name, whereas it should have added
+ a Resent-Sender: header. It erroneously treats any prefix of the
+ username as equal to the username.
+
+ This change corrects that bug.
+