support "sideload over ADB" mode

Rather than depending on the existence of some place to store a file
that is accessible to users on an an unbootable device (eg, a physical
sdcard, external USB drive, etc.), add support for sideloading
packages sent to the device with adb.

This change adds a "minimal adbd" which supports nothing but receiving
a package over adb (with the "adb sideload" command) and storing it to
a fixed filename in the /tmp ramdisk, from where it can be verified
and sideloaded in the usual way.  This should be leave available even
on locked user-build devices.

The user can select "apply package from ADB" from the recovery menu,
which starts minimal-adb mode (shutting down any real adbd that may be
running).  Once minimal-adb has received a package it exits
(restarting real adbd if appropriate) and then verification and
installation of the received package proceeds.

Change-Id: I6fe13161ca064a98d06fa32104e1f432826582f5
diff --git a/minadbd/ b/minadbd/
new file mode 100644
index 0000000..5a4de68
--- /dev/null
+++ b/minadbd/
@@ -0,0 +1,32 @@
+# Copyright 2005 The Android Open Source Project
+# for adb
+LOCAL_PATH:= $(call my-dir)
+# minadbd library
+# =========================================================
+include $(CLEAR_VARS)
+	adb.c \
+	fdevent.c \
+	transport.c \
+	transport_usb.c \
+	sockets.c \
+	services.c \
+	usb_linux_client.c \
+	utils.c
+LOCAL_CFLAGS := -O2 -g -DADB_HOST=0 -Wall -Wno-unused-parameter
+LOCAL_MODULE := libminadbd
+LOCAL_STATIC_LIBRARIES := libcutils libc