scripts/mk: rewrite architecture.mk with explicit loops

Use loops and template code instead of duplicating many similar lines.
This avoids copy&paste typos, is shorter and easier to modify.

Based-on-patch-by: Thorsten Glaser <tg@mirbsd.de>

debian/changelog

@@ -30,6 +30,8 @@ dpkg (1.16.2) UNRELEASED; urgency=low
   [ Raphaël Hertzog ]
   * Update Dpkg::Shlibs to look into multiarch paths when cross-building
     too. Closes: #595144
+  * Rewrite architecture.mk with explicit loops instead of duplicating many
+    similar lines. Based on a patch by Thorsten Glaser <tg@mirbsd.de>.
 
   [ Jonathan Nieder ]
   * Bump po4a version in Build-Depends to 0.41, since earlier versions do

scripts/mk/architecture.mk

@@ -4,22 +4,8 @@
 
 dpkg_late_eval ?= $(or $(value DPKG_CACHE_$(1)),$(eval DPKG_CACHE_$(1) := $(shell $(2)))$(value DPKG_CACHE_$(1)))
 
-DEB_HOST_ARCH ?= $(call dpkg_late_eval,DEB_HOST_ARCH,dpkg-architecture -qDEB_HOST_ARCH)
-DEB_HOST_ARCH_OS ?= $(call dpkg_late_eval,DEB_HOST_ARCH_OS,dpkg-architecture -qDEB_HOST_ARCH_OS)
-DEB_HOST_ARCH_CPU ?= $(call dpkg_late_eval,DEB_HOST_ARCH_CPU,dpkg-architecture -qDEB_HOST_ARCH_CPU)
-DEB_HOST_ARCH_BITS ?= $(call dpkg_late_eval,DEB_HOST_ARCH,dpkg-architecture -qDEB_HOST_ARCH_BITS)
-DEB_HOST_ARCH_ENDIAN ?= $(call dpkg_late_eval,DEB_HOST_ARCH_ENDIAN,dpkg-architecture -qDEB_HOST_ARCH_ENDIAN)
-DEB_HOST_GNU_CPU ?= $(call dpkg_late_eval,DEB_HOST_GNU_CPU,dpkg-architecture -qDEB_HOST_GNU_CPU)
-DEB_HOST_GNU_SYSTEM ?= $(call dpkg_late_eval,DEB_HOST_GNU_SYSTEM,dpkg-architecture -qDEB_HOST_GNU_SYSTEM)
-DEB_HOST_GNU_TYPE ?= $(call dpkg_late_eval,DEB_HOST_GNU_TYPE,dpkg-architecture -qDEB_HOST_GNU_TYPE)
-DEB_HOST_MULTIARCH ?= $(call dpkg_late_eval,DEB_HOST_MULTIARCH,dpkg-architecture -qDEB_HOST_MULTIARCH)
+dpkg_architecture_setvar = $(1) ?= $(call dpkg_late_eval,$(1),dpkg-architecture -q$(1))
 
-DEB_BUILD_ARCH ?= $(call dpkg_late_eval,DEB_BUILD_ARCH,dpkg-architecture -qDEB_BUILD_ARCH)
-DEB_BUILD_ARCH_OS ?= $(call dpkg_late_eval,DEB_BUILD_ARCH_OS,dpkg-architecture -qDEB_BUILD_ARCH_OS)
-DEB_BUILD_ARCH_CPU ?= $(call dpkg_late_eval,DEB_BUILD_ARCH_CPU,dpkg-architecture -qDEB_BUILD_ARCH_CPU)
-DEB_BUILD_ARCH_BITS ?= $(call dpkg_late_eval,DEB_BUILD_ARCH,dpkg-architecture -qDEB_BUILD_ARCH_BITS)
-DEB_BUILD_ARCH_ENDIAN ?= $(call dpkg_late_eval,DEB_BUILD_ARCH_ENDIAN,dpkg-architecture -qDEB_BUILD_ARCH_ENDIAN)
-DEB_BUILD_GNU_CPU ?= $(call dpkg_late_eval,DEB_BUILD_GNU_CPU,dpkg-architecture -qDEB_BUILD_GNU_CPU)
-DEB_BUILD_GNU_SYSTEM ?= $(call dpkg_late_eval,DEB_BUILD_GNU_SYSTEM,dpkg-architecture -qDEB_BUILD_GNU_SYSTEM)
-DEB_BUILD_GNU_TYPE ?= $(call dpkg_late_eval,DEB_BUILD_GNU_TYPE,dpkg-architecture -qDEB_BUILD_GNU_TYPE)
-DEB_BUILD_MULTIARCH ?= $(call dpkg_late_eval,DEB_BUILD_MULTIARCH,dpkg-architecture -qDEB_BUILD_MULTIARCH)
+$(foreach machine,BUILD HOST,\
+  $(foreach var,ARCH ARCH_OS ARCH_CPU ARCH_BITS ARCH_ENDIAN GNU_CPU GNU_SYSTEM GNU_TYPE MULTIARCH,\
+    $(eval $(call dpkg_architecture_setvar,DEB_$(machine)_$(var)))))