Add 'Android.mk' file, fix compile on Android.

This requires disabling LDPRELOAD and temporarily disabling
capabilities support.

Reland of https://android-review.googlesource.com/#/c/159755/
with compile fixes. Compile-tested on
aosp_{x86,x86_64,arm,arm64,mips64}-eng.

Bug: 22487289
Change-Id: Ia4530cf09b074aa0a2afe5a5b307ff3c5c5d6c08
diff --git a/arch.h b/arch.h
index cfe6122..652f072 100644
--- a/arch.h
+++ b/arch.h
@@ -24,6 +24,8 @@
 #    define EM_ARM 40
 #  endif
 #  define ARCH_NR AUDIT_ARCH_ARM
+#elif defined(__aarch64__)
+#  define ARCH_NR AUDIT_ARCH_AARCH64
 #elif defined(__hppa__)
 #  define ARCH_NR AUDIT_ARCH_PARISC
 #elif defined(__ia64__)