install all targets, not just flashfs

Reference: /n/sources/patch/applied/flashfsmk
Date: Wed Aug 25 00:06:59 CES 2010
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/aux/flashfs/mkfile	Wed Aug 25 00:06:07 2010
+++ /sys/src/cmd/aux/flashfs/mkfile	Wed Aug 25 00:06:06 2010
@@ -16,7 +16,7 @@
 	conv.$O\
 	utils.$O\
 
-HDRS=\
+HFILES=\
 	flashfs.h
 
 LIB=/$objtype/lib/lib9p.a
@@ -35,5 +35,3 @@
 
 $O.flashfs: flash.$O journal.$O entry.$O errors.$O request.$O devfs.$O conv.$O utils.$O
 	$LD -o $target $prereq
-
-$ALLOBJ: $HDRS