Use lib64 for mips64 as well.

This was previously working because for some reason prebuilts/ndk had
a tangled mess of hand assembled symlinks that pointed lib -> lib64
for the multilib architectures.

Change-Id: I294d67f58f2008b1a53790cf676f5223df449cbc
diff --git a/core/binary.mk b/core/binary.mk
index ddc4a1b..fb2444c 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -75,7 +75,15 @@
   my_ndk_source_root := $(HISTORICAL_NDK_VERSIONS_ROOT)/current/sources
   my_ndk_sysroot := $(HISTORICAL_NDK_VERSIONS_ROOT)/current/platforms/android-$(LOCAL_SDK_VERSION)/arch-$(TARGET_$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)
   my_ndk_sysroot_include := $(my_ndk_sysroot)/usr/include
-  ifeq (x86_64,$(TARGET_$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH))
+
+  # x86_64 and and mips64 are both multilib toolchains, so their libraries are
+  # installed in /usr/lib64. Aarch64, on the other hand, is not a multilib
+  # compiler, so its libraries are in /usr/lib.
+  #
+  # Mips32r6 is yet another variation, with libraries installed in libr6.
+  #
+  # For the rest, the libraries are installed simply to /usr/lib.
+  ifneq (,$(filter x86_64 mips64,$(TARGET_$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)))
     my_ndk_sysroot_lib := $(my_ndk_sysroot)/usr/lib64
   else ifeq (mips32r6,$(TARGET_$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH_VARIANT))
     my_ndk_sysroot_lib := $(my_ndk_sysroot)/usr/libr6