-DEB_BUILD_PROG:=debuild -us -uc
-APT_DEBVER=$(shell dpkg-parsechangelog |sed -n -e '/^Version:/s/^Version: //p')
+export DEB_HOST_GNU_TYPE ?= $(shell dpkg-architecture -qDEB_HOST_GNU_TYPE)
+export DEB_BUILD_GNU_TYPE ?= $(shell dpkg-architecture -qDEB_BUILD_GNU_TYPE)
+
+# FOR AUTOCONF 2.52 AND NEWER ONLY
+ifeq ($(DEB_BUILD_GNU_TYPE), $(DEB_HOST_GNU_TYPE))
+ confflags += --build $(DEB_HOST_GNU_TYPE)
+else
+ confflags += --build $(DEB_BUILD_GNU_TYPE) --host $(DEB_HOST_GNU_TYPE)
+endif
+
+# See below
+-include build/environment.mak
+
+ifneq (,$(shell which dpkg-buildflags))
+ export CXXFLAGS = $(shell dpkg-buildflags --get CXXFLAGS)
+else
+ ifneq (,$(findstring noopt,$(DEB_BUILD_OPTIONS)))
+ export CXXFLAGS = -O0 -g -Wall
+ else
+ export CXXFLAGS = -O2 -g -Wall
+ endif
+endif
+
+# Default rule
+build:
+
+PKG=apt
+DEB_BUILD_PROG:=debuild --preserve-envvar PATH --preserve-envvar CCACHE_DIR -us -uc $(DEB_BUILD_PROG_OPTS)
+APT_DEBVER=$(shell dpkg-parsechangelog |sed -n -e '/^Version:/s/^Version: //p' | sed -e 's/\+.*$$//')