diff --git a/core/Makefile b/core/Makefile
index 0823995..9cb8c82 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1246,6 +1246,15 @@
 		cd $(dir $@) && zip -rq $(notdir $@) $(PRIVATE_NAME) \
 	) || ( rm -rf $(PRIVATE_DIR) $@ && exit 44 )
 
+
+# Is a Windows SDK requested? If so, we need some definitions from here
+# in order to find the Linux SDK used to create the Windows one.
+ifneq ($(filter win_sdk,$(MAKECMDGOALS)),)
+LINUX_SDK_NAME := $(sdk_name)
+LINUX_SDK_DIR  := $(sdk_dir)
+include $(TOPDIR)development/build/tools/windows_sdk.mk
+endif
+
 endif # !simulator
 
 # -----------------------------------------------------------------
diff --git a/core/config.mk b/core/config.mk
index 3eddc13..a4d3154 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -195,7 +195,6 @@
 YACC:= bison -d
 DOXYGEN:= doxygen
 AAPT := $(HOST_OUT_EXECUTABLES)/aapt$(HOST_EXECUTABLE_SUFFIX)
-ACP := $(HOST_OUT_EXECUTABLES)/acp$(HOST_EXECUTABLE_SUFFIX)
 AIDL := $(HOST_OUT_EXECUTABLES)/aidl$(HOST_EXECUTABLE_SUFFIX)
 ICUDATA := $(HOST_OUT_EXECUTABLES)/icudata$(HOST_EXECUTABLE_SUFFIX)
 SIGNAPK_JAR := $(HOST_OUT_JAVA_LIBRARIES)/signapk$(COMMON_JAVA_PACKAGE_SUFFIX)
@@ -214,6 +213,9 @@
 PROGUARD := external/proguard/bin/proguard.sh
 JAVATAGS := build/tools/java-event-log-tags.py
 
+# ACP is always for the build OS, not for the host OS
+ACP := $(BUILD_OUT_EXECUTABLES)/acp$(BUILD_EXECUTABLE_SUFFIX)
+
 # dx is java behind a shell script; no .exe necessary.
 DX := $(HOST_OUT_EXECUTABLES)/dx
 KCM := $(HOST_OUT_EXECUTABLES)/kcm$(HOST_EXECUTABLE_SUFFIX)
diff --git a/core/envsetup.mk b/core/envsetup.mk
index 6d14753..f8a2027 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -68,9 +68,17 @@
 ifneq (,$(findstring CYGWIN,$(UNAME)))
 	HOST_OS := windows
 endif
+
+# BUILD_OS is the real host doing the build.
+BUILD_OS := $(HOST_OS)
+
+# Under Linux, if USE_MINGW is set, we change HOST_OS to Windows to build the
+# Windows SDK. Only a subset of tools and SDK will manage to build properly.
+ifeq ($(HOST_OS),linux)
 ifneq ($(USE_MINGW),)
 	HOST_OS := windows
 endif
+endif
 
 ifeq ($(HOST_OS),)
 $(error Unable to determine HOST_OS from uname -sm: $(UNAME)!)
@@ -86,6 +94,8 @@
 	HOST_ARCH := ppc
 endif
 
+BUILD_ARCH := $(HOST_ARCH)
+
 ifeq ($(HOST_ARCH),)
 $(error Unable to determine HOST_ARCH from uname -sm: $(UNAME)!)
 endif
@@ -168,6 +178,8 @@
 HOST_OUT_debug := $(HOST_OUT_ROOT_debug)/$(HOST_OS)-$(HOST_ARCH)
 HOST_OUT := $(HOST_OUT_$(HOST_BUILD_TYPE))
 
+BUILD_OUT := $(OUT_DIR)/host/$(BUILD_OS)-$(BUILD_ARCH)
+
 ifeq ($(TARGET_SIMULATOR),true)
   # Any arch- or os-specific parts of the simulator (everything
   # under product/) are actually host-dependent.
@@ -185,6 +197,8 @@
 
 OUT_DOCS := $(TARGET_COMMON_OUT_ROOT)/docs
 
+BUILD_OUT_EXECUTABLES:= $(BUILD_OUT)/bin
+
 HOST_OUT_EXECUTABLES:= $(HOST_OUT)/bin
 HOST_OUT_SHARED_LIBRARIES:= $(HOST_OUT)/lib
 HOST_OUT_JAVA_LIBRARIES:= $(HOST_OUT)/framework
diff --git a/core/main.mk b/core/main.mk
index 014c050..f830f03 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -179,6 +179,9 @@
 ifneq ($(filter sdk,$(MAKECMDGOALS)),)
 is_sdk_build := true
 endif
+ifneq ($(filter win_sdk,$(MAKECMDGOALS)),)
+is_sdk_build := true
+endif
 ifneq ($(filter sdk_addon,$(MAKECMDGOALS)),)
 is_sdk_build := true
 endif
@@ -254,6 +257,7 @@
 ifneq ($(words $(filter-out $(INTERNAL_MODIFIER_TARGETS),$(MAKECMDGOALS))),1)
 $(error The 'sdk' target may not be specified with any other targets)
 endif
+
 # TODO: this should be eng I think.  Since the sdk is built from the eng
 # variant.
 tags_to_install := user debug eng