It appeared in revision 1.3 ("Update from lite2.")
It's the only one in the string family that has it, and nothing from it
is used.
Index: strsep.c
===================================================================
RCS file: /cvs/src/lib/libc/string/strsep.c,v
retrieving revision 1.6
diff -u -p -r1.6 strsep.c
--- strsep.c 8 Aug 2005 08:05:37 -0000 1.6
+++ strsep.c 25 Jan 2014 06:41:18 -0000
@@ -30,7 +30,6 @@
*/
#include <string.h>
-#include <stdio.h>
/*
* Get next token from string *stringp, where tokens are possibly-empty
