build/make/Android.mk: support TARGET_ARCH_ABI=x86_64

requires r10e or newer:

Android NDK, Revision 10e (May 2015)
...
Other bug fixes:
...
  - Fixed .asm support for ABI x86_64.

Change-Id: I51ec9a5f77c982b7412d922e896348a83ae2d7d6
diff --git a/README b/README
index 7b44ba7..3adc551 100644
--- a/README
+++ b/README
@@ -85,6 +85,7 @@
     x86-win32-vs10
     x86-win32-vs11
     x86-win32-vs12
+    x86_64-android-gcc
     x86_64-darwin9-gcc
     x86_64-darwin10-gcc
     x86_64-darwin11-gcc
diff --git a/build/make/Android.mk b/build/make/Android.mk
index e971c9d..aa7a8c9 100644
--- a/build/make/Android.mk
+++ b/build/make/Android.mk
@@ -67,6 +67,8 @@
   LOCAL_ARM_MODE := arm
 else ifeq ($(TARGET_ARCH_ABI),x86)
   include $(CONFIG_DIR)libs-x86-android-gcc.mk
+else ifeq ($(TARGET_ARCH_ABI),x86_64)
+  include $(CONFIG_DIR)libs-x86_64-android-gcc.mk
 else ifeq ($(TARGET_ARCH_ABI),mips)
   include $(CONFIG_DIR)libs-mips-android-gcc.mk
 else
diff --git a/configure b/configure
index 6cac15a..fcab145 100755
--- a/configure
+++ b/configure
@@ -132,6 +132,7 @@
 all_platforms="${all_platforms} x86-win32-vs10"
 all_platforms="${all_platforms} x86-win32-vs11"
 all_platforms="${all_platforms} x86-win32-vs12"
+all_platforms="${all_platforms} x86_64-android-gcc"
 all_platforms="${all_platforms} x86_64-darwin9-gcc"
 all_platforms="${all_platforms} x86_64-darwin10-gcc"
 all_platforms="${all_platforms} x86_64-darwin11-gcc"