Add 64-bit windows cross-compiles

This is mostly the same as the existing 2ND_HOST / HOST_CROSS support.

The interesting thing I did here was make x86 the 'first' architecture,
and x86_64 the second. This way LOCAL_MULTILIB := first defaults to
32-bit windows modules.

  windows-x86/bin   <- defaults to 32-bit executables
  windows-x86/lib   <- 32-bit libraries, like before
  windows-x86/lib64 <- 64-bit libraries
  windows-x86/obj   <- 32-bit intermediates
  windows-x86/obj64 <- 64-bit intermediates

Then modules are registered with the names:

  host_cross_liblog    <- 32-bit, like before
  host_cross_liblog_64 <- 64-bit

Bug: 26957718

(cherry picked from commit 9ecbf83259)

Change-Id: Iab2d36e20d7002568c3534e7781e9ac8ab21a4a9

core/host_static_library.mk

@@ -49,6 +49,21 @@ LOCAL_INTERMEDIATE_TARGETS :=
 
 include $(BUILD_SYSTEM)/host_static_library_internal.mk
 endif
+
+ifdef HOST_CROSS_2ND_ARCH
+LOCAL_2ND_ARCH_VAR_PREFIX := $(HOST_CROSS_2ND_ARCH_VAR_PREFIX)
+include $(BUILD_SYSTEM)/module_arch_supported.mk
+ifeq ($(my_module_arch_supported),true)
+# Build for HOST_CROSS_2ND_ARCH
+OVERRIDE_BUILT_MODULE_PATH :=
+LOCAL_BUILT_MODULE :=
+LOCAL_INSTALLED_MODULE :=
+LOCAL_INTERMEDIATE_TARGETS :=
+
+include $(BUILD_SYSTEM)/host_static_library_internal.mk
+endif
+LOCAL_2ND_ARCH_VAR_PREFIX :=
+endif
 LOCAL_HOST_PREFIX :=
 endif