Build System: Resolve CPU-specific logic in common build files

* tools/Config.mk - Add empty definition POSTBUILD
* tools/Makefile.unix/win - Replace CXD56xx specific logic with $(call POSTBUILD)
* boards/arm/cxd56xx/scripts/cxd56xx_Config.mk - Add POSTBUILD definitions with logic removed from Makefile.unix/win
* boards/arm/cxd56xx/spresense/scripts/Make.defs - Include cxd56xx_Config.mk immediately after tools/Config.mk so that the empty POSTBUILD definition will be replaced with the correct one

NOTE: There is a precedent for this approach.  This is the way that other architecture-specific build options are implemented.  See, for example, tools/zds/zds_Config.mk

boards/arm/cxd56xx/scripts/cxd56xx_Config.mk

@@ -0,0 +1,41 @@
+############################################################################
+# board/arm/cxd56xx/script/cxd56xx_Config.defs
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership. The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License. You may obtain a copy of the License at
+#
+# http:https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+# These are the macros that will be used in the NuttX make system to compile
+# and assembly source files and to insert the resulting object files into an
+# archive. These replace the default definitions at tools/Config.mk
+
+# POSTBUILD -- Perform post build operations
+
+ifeq ($(CONFIG_CXD56_BINARY),y)
+define POSTBUILD
+ $(Q) if [ ! -f "tools/cxd56/mkspk" ] ; then \
+ echo ""; \
+ echo "Please run the following command to build the needed tool"; \
+ echo ""; \
+ echo "cd tools/cxd56 && make && cd ../.."; \
+ echo ""; \
+ echo "run make again to create the nuttx.spk image."; \
+ else \
+ echo "Generating: $(NUTTXNAME).spk"; \
+ tools/cxd56/mkspk -c2 nuttx nuttx nuttx.spk; \
+ fi
+endef
+endif

boards/arm/cxd56xx/spresense/scripts/Make.defs

@@ -35,6 +35,7 @@
 
 include ${TOPDIR}/.config
 include ${TOPDIR}/tools/Config.mk
+include ${TOPDIR}/boards/arm/cxd56xx/scripts/cxd56xx_Config.mk
 include ${TOPDIR}/arch/arm/src/armv7-m/Toolchain.defs
 
 # Setup for the kind of memory that we are executing from

tools/Config.mk

@@ -2,7 +2,7 @@
 # tools/Config.mk
 # Global build rules and macros.
 #
-# Copyright (C) 2011, 2013-2014, 2018-2019 Gregory Nutt. All rights
+# Copyright (C) 2011, 2013-2014, 2018-2019, 2020 Gregory Nutt. All rights
 # reserved.
 # Author: Richard Cochran
 # Gregory Nutt <[email protected]>
@@ -239,6 +239,15 @@ define PRELINK
 endef
 endif
 
+# POSTBUILD -- Perform post build operations
+# Some architectures require the use of special tools and special handling
+# AFTER building the NuttX binary. Make.defs files for thos architectures
+# should override the following define with the correct operations for
+# that platform
+
+define POSTBUILD
+endef
+
 # DELFILE - Delete one file
 
 ifeq ($(CONFIG_WINDOWS_NATIVE),y)

tools/Makefile.unix

@@ -480,19 +480,6 @@ ifeq ($(CONFIG_RAW_BINARY),y)
  @echo "CP: $(NUTTXNAME).bin"
  $(Q) $(OBJCOPY) $(OBJCOPYARGS) -O binary $(BIN) $(NUTTXNAME).bin
 endif
-ifeq ($(CONFIG_CXD56_BINARY),y)
- $(Q) if [ ! -f "tools/cxd56/mkspk" ] ; then \
- echo ""; \
- echo "Please run the following command to build the needed tool"; \
- echo ""; \
- echo "cd tools/cxd56 && make && cd ../.."; \
- echo ""; \
- echo "run make again to create the nuttx.spk image."; \
- else \
- echo "Generating: $(NUTTXNAME).spk"; \
- tools/cxd56/mkspk -c2 nuttx nuttx nuttx.spk; \
- fi
-endif
 ifeq ($(CONFIG_UBOOT_UIMAGE),y)
  @echo "MKIMAGE: uImage"
  $(Q) mkimage -A $(CONFIG_ARCH) -O linux -C none -T kernel -a $(CONFIG_UIMAGE_LOAD_ADDRESS) \
@@ -501,6 +488,7 @@ ifeq ($(CONFIG_UBOOT_UIMAGE),y)
  cp -f uImage /tftpboot/uImage; \
  fi
 endif
+ $(call POSTBUILD)
 
 # $(BIN)
 #

tools/Makefile.win

@@ -490,19 +490,7 @@ ifeq ($(CONFIG_RAW_BINARY),y)
  @echo "CP: $(NUTTXNAME).bin"
  $(Q) $(OBJCOPY) $(OBJCOPYARGS) -O binary $(BIN) $(NUTTXNAME).bin
 endif
-ifeq ($(CONFIG_CXD56_BINARY),y)
- $(Q) if [ ! -f "tools/cxd56/mkspk.exe" ] ; then \
- echo ""; \
- echo "Please run the following command to build the needed tool"; \
- echo ""; \
- echo "cd tools/cxd56 && make && cd ../.."; \
- echo ""; \
- echo "run make again to create the nuttx.spk image."; \
- else \
- echo "Generating: $(NUTTXNAME).spk"; \
- tools\cxd56\mkspk.exe -c2 nuttx nuttx nuttx.spk; \
- fi
-endif
+ $(call POSTBUILD)
 
 # $(BIN)
 #

tools/zds/zds_Config.mk

@@ -1,5 +1,5 @@
 ############################################################################
-# tools/zds/zds_Config.defs
+# tools/zds/zds_Config.mk
 #
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements. See the NOTICE file distributed with