kbuild: deb-pkg: split debian/rules

debian/rules is generated by shell, but the escape sequence (\$) is
unreadable.

debian/rules embeds only two variables (ARCH and KERNELRELEASE).

Split them out to debian/rules.vars, and check-in the rest of Makefile
code to scripts/package/debian/rules.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

scripts/package/debian/rules

+#!/usr/bin/make -f
+# SPDX-License-Identifier: GPL-2.0-only
+
+include debian/rules.vars
+
+srctree ?= .
+
+.PHONY: binary binary-indep binary-arch
+binary: binary-arch binary-indep
+binary-indep: build-indep
+binary-arch: build-arch
+	$(MAKE) -f $(srctree)/Makefile ARCH=$(ARCH) \
+	KERNELRELEASE=$(KERNELRELEASE) \
+	run-command KBUILD_RUN_COMMAND=+$(srctree)/scripts/package/builddeb
+
+.PHONY: build build-indep build-arch
+build: build-arch build-indep
+build-indep:
+build-arch:
+	$(MAKE) -f $(srctree)/Makefile ARCH=$(ARCH) \
+	KERNELRELEASE=$(KERNELRELEASE) \
+	$(shell $(srctree)/scripts/package/deb-build-option) \
+	olddefconfig all
+
+.PHONY: clean
+clean:
+	rm -rf debian/files debian/linux-*
+	$(MAKE) -f $(srctree)/Makefile ARCH=$(ARCH) clean

scripts/package/mkdebian

@@ -263,35 +263,11 @@ Description: Linux kernel debugging symbols for $version
 EOF
 fi
 
-cat <<EOF > debian/rules
-#!/usr/bin/make -f
-
-srctree ?= .
-KERNELRELEASE = ${KERNELRELEASE}
-
-.PHONY: clean build build-arch build-indep binary binary-arch binary-indep
-
-build-indep:
-build-arch:
-	\$(MAKE) -f \$(srctree)/Makefile ARCH=${ARCH} \
-	KERNELRELEASE=\$(KERNELRELEASE) \
-	\$(shell \$(srctree)/scripts/package/deb-build-option) \
-	olddefconfig all
-
-build: build-arch
-
-binary-indep:
-binary-arch: build-arch
-	\$(MAKE) -f \$(srctree)/Makefile ARCH=${ARCH} \
-	KERNELRELEASE=\$(KERNELRELEASE) \
-	run-command KBUILD_RUN_COMMAND=+\$(srctree)/scripts/package/builddeb
-
-clean:
-	rm -rf debian/files debian/linux-*
-	\$(MAKE) -f \$(srctree)/Makefile ARCH=${ARCH} clean
-
-binary: binary-arch
+cat <<EOF > debian/rules.vars
+ARCH := ${ARCH}
+KERNELRELEASE := ${KERNELRELEASE}
 EOF
-chmod +x debian/rules
+
+cp "${srctree}/scripts/package/debian/rules" debian/
 
 exit 0