Add ld.config.txt to rootdir/etc

This file is used by linker to create custom namespace
configuration for binaries.

Bug: http://b/30706810
Test: m
Change-Id: Ifc4e43ed51c6906c75a7f0d9f00a816b5e16c4d8
diff --git a/target/product/core_minimal.mk b/target/product/core_minimal.mk
index fe1a382..701a69c 100644
--- a/target/product/core_minimal.mk
+++ b/target/product/core_minimal.mk
@@ -125,6 +125,9 @@
 PRODUCT_COPY_FILES += \
     system/core/rootdir/etc/public.libraries.android.txt:system/etc/public.libraries.txt
 
+PRODUCT_COPY_FILES += \
+    system/core/rootdir/etc/ld.config.txt:system/etc/ld.config.txt
+
 # Different dexopt types for different package update/install times.
 # On eng builds, make "boot" reasons do pure JIT for faster turnaround.
 ifeq (eng,$(TARGET_BUILD_VARIANT))