First parts of enabling a host Dalvik build.

Most of this is just factoring out common make defs to include both on
the host and device side, though there is a little bit of code change
to be slightly POSIX friendlier and to avoid unnecessary sanity checks
when compiling without an asm version of the interpreter.

This patch should cause no difference in build results, except if you
turn on the newly-defined WITH_HOST_DALVIK build flag. If you do turn
it on, at this point you should probably expect the build to fail due
to insufficient dependencies, which I of course expect to address in
upcoming patches.
diff --git a/Android.mk b/Android.mk
index 5f553c5..aa4be86 100644
--- a/Android.mk
+++ b/Android.mk
@@ -1,20 +1,36 @@
-LOCAL_PATH := $(call my-dir)
-include $(CLEAR_VARS)
+# Copyright (C) 2009 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
-LOCAL_SRC_FILES := \
+
+LOCAL_PATH := $(call my-dir)
+
+#
+# Common definitions for host and device.
+#
+
+src_files := \
 	JNIHelp.c \
 	Register.c
 
-LOCAL_C_INCLUDES += \
+c_includes := \
 	$(JNI_H_INCLUDE)
 
 # Any shared/static libs required by libjavacore
 # need to be mentioned here as well.
 # TODO: fix this requirement
 
-LOCAL_SHARED_LIBRARIES := \
-	liblog \
-	libcutils \
+shared_libraries := \
 	libexpat \
 	libssl \
 	libutils \
@@ -25,10 +41,51 @@
 	libicui18n \
 	libsqlite
 
-LOCAL_STATIC_LIBRARIES := \
+static_libraries := \
 	libjavacore \
 	libfdlibm
 
+
+
+#
+# Build for the target (device).
+#
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := $(src_files)
+LOCAL_C_INCLUDES := $(c_includes)
+LOCAL_SHARED_LIBRARIES := $(shared_libraries)
+LOCAL_STATIC_LIBRARIES := $(static_libraries)
+
+# liblog and libcutils are shared for target.
+LOCAL_SHARED_LIBRARIES += \
+	liblog libcutils
+
 LOCAL_MODULE := libnativehelper
 
 include $(BUILD_SHARED_LIBRARY)
+
+
+#
+# Build for the host.
+#
+
+ifeq ($(WITH_HOST_DALVIK),true)
+
+    include $(CLEAR_VARS)
+
+    LOCAL_SRC_FILES := $(src_files)
+    LOCAL_C_INCLUDES := $(c_includes)
+    LOCAL_SHARED_LIBRARIES := $(shared_libraries)
+    LOCAL_STATIC_LIBRARIES := $(static_libraries)
+
+    # liblog and libcutils are static for host.
+    LOCAL_STATIC_LIBRARIES += \
+        liblog libcutils
+
+    LOCAL_MODULE := libnativehelper-host
+
+    include $(BUILD_HOST_SHARED_LIBRARY)
+
+endif