kbuild: slim down package for building external modules

Exclude directories and files unnecessary for building external modules:

 - include/config/  (except include/config/{auto.conf,kernel.release})
 - scripts/atomic/
 - scripts/dtc/
 - scripts/kconfig/
 - scripts/mod/mk_elfconfig
 - scripts/package/
 - scripts/unifdef
 - .config
 - *.o
 - .*.cmd

Avoid copying files twice for the following directories:

 - include/generated/
 - arch/*/include/generated/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

scripts/package/install-extmod-build

@@ -9,15 +9,22 @@ is_enabled() {
 	grep -q "^$1=y" include/config/auto.conf
 }
 
+find_in_scripts() {
+	find scripts \
+		\( -name atomic -o -name dtc -o -name kconfig -o -name package \) -prune -o \
+		! -name unifdef -a ! -name mk_elfconfig -a \( -type f -o -type l \) -print
+}
+
 mkdir -p "${destdir}"
 
 (
 	cd "${srctree}"
 	echo Makefile
 	find "arch/${SRCARCH}" -maxdepth 1 -name 'Makefile*'
-	find include scripts -type f -o -type l
+	find "arch/${SRCARCH}" -name generated -prune -o -name include -type d -print
 	find "arch/${SRCARCH}" -name Kbuild.platforms -o -name Platform
-	find "arch/${SRCARCH}" -name include -type d
+	find include \( -name config -o -name generated \) -prune -o \( -type f -o -type l \) -print
+	find_in_scripts
 ) | tar -c -f - -C "${srctree}" -T - | tar -xf - -C "${destdir}"
 
 {
@@ -25,12 +32,16 @@ mkdir -p "${destdir}"
 		echo tools/objtool/objtool
 	fi
 
-	find "arch/${SRCARCH}/include" Module.symvers include scripts -type f
+	echo Module.symvers
+	echo "arch/${SRCARCH}/include/generated"
+	echo include/config/auto.conf
+	echo include/config/kernel.release
+	echo include/generated
+	find_in_scripts
 
 	if is_enabled CONFIG_GCC_PLUGINS; then
 		find scripts/gcc-plugins -name '*.so'
 	fi
 } | tar -c -f - -T - | tar -xf - -C "${destdir}"
 
-# copy .config manually to be where it's expected to be
-cp "${KCONFIG_CONFIG}" "${destdir}/.config"
+find "${destdir}" \( -name '.*.cmd' -o -name '*.o' \) -delete