Add HOST_PREFER_32_BIT to support 32-bit-by-default multilib build

We already support pure 32-bit and 64-bit-by-default multilib build.
With HOST_PREFER_32_BIT we can build 32-bit-by-default multilib build.
This will be lest disruptive during the period we transition to
64-bit-by-default.

Bug: 13751317
Change-Id: I0d56ce4abbe4afeaacfd70d709f6a349791c0722
diff --git a/core/host_shared_library.mk b/core/host_shared_library.mk
index de5e6ad..2fdf61f 100644
--- a/core/host_shared_library.mk
+++ b/core/host_shared_library.mk
@@ -2,9 +2,13 @@
 include $(BUILD_SYSTEM)/multilib.mk
 
 ifndef my_module_multilib
+ifeq ($(HOST_PREFER_32_BIT),true)
+my_module_multilib := 32
+else
 # By default we only build host module for the first arch.
 my_module_multilib := first
 endif
+endif
 
 LOCAL_2ND_ARCH_VAR_PREFIX :=
 include $(BUILD_SYSTEM)/module_arch_supported.mk
@@ -21,9 +25,6 @@
 OVERRIDE_BUILT_MODULE_PATH :=
 LOCAL_BUILT_MODULE :=
 LOCAL_INSTALLED_MODULE :=
-LOCAL_MODULE_STEM :=
-LOCAL_BUILT_MODULE_STEM :=
-LOCAL_INSTALLED_MODULE_STEM :=
 LOCAL_INTERMEDIATE_TARGETS :=
 
 include $(BUILD_SYSTEM)/host_shared_library_internal.mk