Make dt_runpath work for libraries opened from apk

This patch also fixes realpath for libraries opened directly
from apks.

Bug: http://b/21960914
Bug: http://b/21961857
Change-Id: I35ade661c87f1d448191f385811f6e9fd3cacf11
diff --git a/linker/Android.mk b/linker/Android.mk
index a962c76..585a738 100644
--- a/linker/Android.mk
+++ b/linker/Android.mk
@@ -12,6 +12,7 @@
     linker_libc_support.c \
     linker_memory.cpp \
     linker_phdr.cpp \
+    linker_utils.cpp \
     rt.cpp \
 
 LOCAL_SRC_FILES_arm     := arch/arm/begin.S