From https://github.com/crystax/android-toolchain-gcc-5/commit/1e57465b9b81699ce8eb603dd4794a839a74c635

diff -N -u -r ../gcc-5.3.0/gcc/config/aarch64/aarch64-linux-android.h ./gcc/config/aarch64/aarch64-linux-android.h
--- ../gcc-5.3.0/gcc/config/aarch64/aarch64-linux-android.h	1969-12-31 19:00:00.000000000 -0500
+++ ./gcc/config/aarch64/aarch64-linux-android.h	2016-03-19 21:08:15.423913071 -0400
@@ -0,0 +1,59 @@
+/* Machine description for AArch64 architecture.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   GCC is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef GCC_AARCH64_LINUX_ANDROID_H
+#define GCC_AARCH64_LINUX_ANDROID_H
+
+
+#undef TARGET_OS_CPP_BUILTINS
+#define TARGET_OS_CPP_BUILTINS()		\
+  do						\
+    {						\
+	GNU_USER_TARGET_OS_CPP_BUILTINS();	\
+	ANDROID_TARGET_OS_CPP_BUILTINS();	\
+    }						\
+  while (0)
+
+#undef  LINK_SPEC
+#define LINK_SPEC							\
+  LINUX_OR_ANDROID_LD (LINUX_TARGET_LINK_SPEC,				\
+		       LINUX_TARGET_LINK_SPEC " " ANDROID_LINK_SPEC)
+
+#undef  CC1_SPEC
+#define CC1_SPEC							\
+  LINUX_OR_ANDROID_CC (GNU_USER_TARGET_CC1_SPEC,			\
+		       GNU_USER_TARGET_CC1_SPEC " " ANDROID_CC1_SPEC)
+
+#define CC1PLUS_SPEC \
+  LINUX_OR_ANDROID_CC ("", ANDROID_CC1PLUS_SPEC)
+
+#undef  LIB_SPEC
+#define LIB_SPEC							\
+  LINUX_OR_ANDROID_LD (GNU_USER_TARGET_LIB_SPEC,			\
+		    GNU_USER_TARGET_NO_PTHREADS_LIB_SPEC " " ANDROID_LIB_SPEC)
+
+#undef	STARTFILE_SPEC
+#define STARTFILE_SPEC \
+  LINUX_OR_ANDROID_LD (GNU_USER_TARGET_STARTFILE_SPEC, ANDROID_STARTFILE_SPEC)
+
+#undef	ENDFILE_SPEC
+#define ENDFILE_SPEC \
+  LINUX_OR_ANDROID_LD (GNU_USER_TARGET_ENDFILE_SPEC, ANDROID_ENDFILE_SPEC)
+
+#endif  /* GCC_AARCH64_LINUX_ANDROID_H */