Fix LIBDIR variable.

Turns out to be easier to keep the leading slash in PRELOADPATH.

Bug: None
Change-Id: I65200f892cbc113506b0fcebc8bdc0bb9c87f2c5
diff --git a/Makefile b/Makefile
index 466d9f1..25e6494 100644
--- a/Makefile
+++ b/Makefile
@@ -4,9 +4,9 @@
 
 include common.mk
 
-LIBDIR ?= /lib
+LIBDIR ?= lib
 PRELOADNAME = libminijailpreload.so
-PRELOADPATH = \"$(LIBDIR)/$(PRELOADNAME)\"
+PRELOADPATH = \"/$(LIBDIR)/$(PRELOADNAME)\"
 CPPFLAGS += -DPRELOADPATH="$(PRELOADPATH)"
 
 ifneq ($(HAVE_SECUREBITS_H),no)