checksrc: detect strtok() use

... as that function slipped through once before.

lib/checksrc.pl

@@ -423,6 +423,7 @@ sub scanfile {
         # scan for use of banned functions
         if($l =~ /^(.*\W)
                    (gets|
+	            strtok|
                     v?sprintf|
                     (str|_mbs|_tcs|_wcs)n?cat|
                     LoadLibrary(Ex)?(A|W)?)