hw-config-defs.h: Remove from source tree + auto-generate

This patch modifies the emulator's build system to place the
auto-generated file android/avd/hw-config-defs.h into the build
directory. Before that, the file was placed in the source tree.

+ Fix the standalone build system to properly deal with
  generated source file dependencies + LOCAL_C_INCLUDES

Change-Id: I4e77cd20bf4ca21f79d5dd19f27724bd8be53a79
diff --git a/Makefile.target b/Makefile.target
index 5f7a8b2..ccc86b4 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -86,6 +86,8 @@
     usb.c \
     watchdog.c
 
+$(call gen-hw-config-defs)
+
 ifeq ($(EMULATOR_TARGET_ARCH),arm)
 HW_SOURCES += android_arm.c \
     arm_pic.c \
@@ -277,6 +279,7 @@
 
 $(call gen-hx-header,qemu-monitor.hx,qemu-monitor.h,monitor.c)
 $(call gen-hx-header,qemu-options.hx,qemu-options.def,vl-android.c qemu-options.h)
+$(call gen-hw-config-defs)
 
 ifeq ($(HOST_OS),darwin)
     FRAMEWORKS := OpenGL Cocoa QuickTime ApplicationServices Carbon IOKit
@@ -356,6 +359,7 @@
 
 $(call gen-hx-header,qemu-monitor.hx,qemu-monitor.h,monitor.c)
 $(call gen-hx-header,qemu-options.hx,qemu-options.def,vl-android.c qemu-options.h)
+$(call gen-hw-config-defs)
 
 # The following files cannot be in static libraries because they contain
 # constructor functions that are otherwise stripped by the final linker