From https://github.com/crystax/android-toolchain-gcc-6/blob/master/gcc/config/aarch64/aarch64-linux.h

diff -u -r ../gcc-6.1.0/gcc/config/aarch64/aarch64-linux.h ./gcc/config/aarch64/aarch64-linux.h
--- ../gcc-6.1.0/gcc/config/aarch64/aarch64-linux.h	2016-03-10 08:29:48.000000000 -0500
+++ ./gcc/config/aarch64/aarch64-linux.h	2016-04-29 04:12:35.207444421 -0400
@@ -21,7 +21,14 @@
 #ifndef GCC_AARCH64_LINUX_H
 #define GCC_AARCH64_LINUX_H
 
-#define GLIBC_DYNAMIC_LINKER "/lib/ld-linux-aarch64%{mbig-endian:_be}%{mabi=ilp32:_ilp32}.so.1"
+#ifndef RUNTIME_ROOT_PREFIX
+#define RUNTIME_ROOT_PREFIX ""
+#endif
+#define GLIBC_DYNAMIC_LINKER RUNTIME_ROOT_PREFIX "/lib/ld-linux-aarch64%{mbig-endian:_be}%{mabi=ilp32:_ilp32}.so.1"
+#ifdef BIONIC_DYNAMIC_LINKER
+#undef BIONIC_DYNAMIC_LINKER
+#endif
+#define BIONIC_DYNAMIC_LINKER RUNTIME_ROOT_PREFIX "/system/bin/linker64"
 
 #undef MUSL_DYNAMIC_LINKER
 #define MUSL_DYNAMIC_LINKER "/lib/ld-musl-aarch64%{mbig-endian:_be}%{mabi=ilp32:_ilp32}.so.1"