make applypatch into a static library

Turn the bulk of applypatch into a static library so it can be used
from the updater.  Also build it as a standalone executable for use by
the existing OTA mechanism.
diff --git a/tools/applypatch/Android.mk b/tools/applypatch/Android.mk
index c25e0d6..fe317ff 100644
--- a/tools/applypatch/Android.mk
+++ b/tools/applypatch/Android.mk
@@ -18,11 +18,22 @@
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := applypatch.c bsdiff.c freecache.c imgpatch.c
+LOCAL_MODULE := libapplypatch
+LOCAL_MODULE_TAGS := eng
+LOCAL_C_INCLUDES += external/bzip2 external/zlib bootable/recovery
+LOCAL_STATIC_LIBRARIES += libmtdutils libmincrypt libbz libz
+
+include $(BUILD_STATIC_LIBRARY)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := main.c
 LOCAL_MODULE := applypatch
 LOCAL_FORCE_STATIC_EXECUTABLE := true
 LOCAL_MODULE_TAGS := eng
-LOCAL_C_INCLUDES += external/bzip2 external/zlib bootable/recovery
-LOCAL_STATIC_LIBRARIES += libmtdutils libmincrypt libbz libz libc
+LOCAL_STATIC_LIBRARIES += libapplypatch
+LOCAL_STATIC_LIBRARIES += libmtdutils libmincrypt libbz libz
+LOCAL_STATIC_LIBRARIES += libcutils libstdc++ libc
 
 include $(BUILD_EXECUTABLE)