Host builds: add fastboot and adb

Add fastboot and adb host utilities to debug builds for debugging
and development purposes.

Change-Id: If77699a27497b8641998930f14d4ee418b856080
diff --git a/fastboot/Android.mk b/fastboot/Android.mk
index 92e9219..5e0e172 100644
--- a/fastboot/Android.mk
+++ b/fastboot/Android.mk
@@ -20,6 +20,7 @@
   $(LOCAL_PATH)/../../extras/ext4_utils
 LOCAL_SRC_FILES := protocol.c engine.c bootimg.c fastboot.c
 LOCAL_MODULE := fastboot
+LOCAL_MODULE_TAGS := debug
 
 ifeq ($(HOST_OS),linux)
   LOCAL_SRC_FILES += usb_linux.c util_linux.c