Make libfis compile with the rest

Reference: /n/patches.lsub.org/patch/fismkfile
Date: Sat Apr 28 18:19:45 CES 2012
Signed-off-by: paurea@lsub.org

--- /sys/src/mkfile	Thu Apr 26 11:22:03 2012
+++ /sys/src/mkfile	Sat Apr 28 17:25:31 2012
@@ -15,6 +15,7 @@
 	libdisk\
 	libdraw\
 	liberror\
+	libfis\
 	libflate\
 	libframe\
 	libgeometry\