7018429: JPRT: Update Makefile to use ALT_JDK_TARGET_IMPORT_PATH for copying JDK

Summary: Set JDK_IMPORT_PATH to  ALT_JDK_TARGET_IMPORT_PATH if it is defined
Reviewed-by: phh, ohair

make/Makefile

 #
-# Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -43,6 +43,7 @@
 #  ALT_OUTPUTDIR              Output directory to use for hotspot build
 #  ALT_EXPORT_PATH            Directory to export hotspot build to
 #  ALT_JDK_IMPORT_PATH        Current JDK build (only for create_jdk rules)
+#  ALT_JDK_TARGET_IMPORT_PATH Current JDK build when cross-compiling
 #  ALT_BUILD_WIN_SA           Building SA on Windows is disabled by default.
 #                             Set ALT_BUILD_WIN_SA=1 to enable building SA on
 #                             Windows.

make/defs.make

 #
-# Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2006, 2011, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -162,6 +162,13 @@ ifneq ($(ALT_JDK_IMPORT_PATH),)
   JDK_IMPORT_PATH=$(ALT_JDK_IMPORT_PATH)
 endif
 
+# Other parts of JDK build may require an import JDK that can be executed
+# on the build host. For cross-compile builds we also need an import JDK
+# that matches the target arch, so for that we set ALT_JDK_TARGET_IMPORT_PATH
+ifneq ($(ALT_JDK_TARGET_IMPORT_PATH),)
+  JDK_IMPORT_PATH=$(ALT_JDK_TARGET_IMPORT_PATH)
+endif
+
 # Find JDK used for javac compiles
 BOOTDIR=$(SLASH_JAVA)/re/j2se/$(PREVIOUS_JDK_VERSION)/latest/binaries/$(PLATFORM)
 ifneq ($(ALT_BOOTDIR),)