unifdefall(1) on FreeBSD
The text 2b495130b46c, as FreeBSD 8.2-RELEASE shipped it.
remove preprocessor conditionals from code
Flags it lists
-
-B -
-D -
-I -
-K -
-U -
-b -
-c -
-d -
-e -
-iD -
-iU -
-k -
-n -
-s -
-t