debian: make cross-compile work

This allows e.g. "sbuild --host=arm64" to build packages for other
architectures on, say, fat amd64 servers.  As a side effect, the Debian
build uses a separate builddir, which helps noting issues on that front.

Signed-off-by: David Lamparter <equinox@diac24.net>

debian/changelog

@@ -1,3 +1,9 @@
+frr (7.3-2) UNRELEASED; urgency=medium
+
+  * allow cross-compile with sbuild --host
+
+ -- David Lamparter <equinox-debian@diac24.net>  Tue, 07 Apr 2020 16:39:43 +0200
+
 frr (7.3-1) unstable; urgency=medium
 
   * new upstream release

debian/control

@@ -26,10 +26,10 @@ Build-Depends:
  libsystemd-dev <!pkg.frr.nosystemd>,
  libyang-dev (>= 0.16.74),
  pkg-config,
- python3,
- python3-dev,
- python3-sphinx,
- python3-pytest <!nocheck>,
+ python3:native,
+ python3-dev:native,
+ python3-sphinx:native,
+ python3-pytest:native <!nocheck>,
  texinfo (>= 4.7)
 Standards-Version: 4.4.1
 Homepage: https://www.frrouting.org/

debian/frr-doc.info

@@ -1 +1 @@
-doc/user/_build/texinfo/frr.info
+build/doc/user/_build/texinfo/frr.info

debian/frr-doc.install

@@ -3,7 +3,7 @@ usr/share/doc/frr/html
 
 # info + images referenced by it
 usr/share/info/
-doc/user/_build/texinfo/*.png usr/share/info
+build/doc/user/_build/texinfo/*.png usr/share/info
 
 # other
 README.md         usr/share/doc/frr

debian/frr.manpages

@@ -1,16 +1,16 @@
-doc/manpages/_build/man/frr-bgpd.8
-doc/manpages/_build/man/frr-eigrpd.8
-doc/manpages/_build/man/frr-fabricd.8
-doc/manpages/_build/man/frr-isisd.8
-doc/manpages/_build/man/frr-ldpd.8
-doc/manpages/_build/man/frr-nhrpd.8
-doc/manpages/_build/man/frr-ospf6d.8
-doc/manpages/_build/man/frr-ospfd.8
-doc/manpages/_build/man/frr-pimd.8
-doc/manpages/_build/man/frr-ripd.8
-doc/manpages/_build/man/frr-ripngd.8
-doc/manpages/_build/man/frr-watchfrr.8
-doc/manpages/_build/man/frr-zebra.8
-doc/manpages/_build/man/frr.1
-doc/manpages/_build/man/mtracebis.8
-doc/manpages/_build/man/vtysh.1
+build/doc/manpages/_build/man/frr-bgpd.8
+build/doc/manpages/_build/man/frr-eigrpd.8
+build/doc/manpages/_build/man/frr-fabricd.8
+build/doc/manpages/_build/man/frr-isisd.8
+build/doc/manpages/_build/man/frr-ldpd.8
+build/doc/manpages/_build/man/frr-nhrpd.8
+build/doc/manpages/_build/man/frr-ospf6d.8
+build/doc/manpages/_build/man/frr-ospfd.8
+build/doc/manpages/_build/man/frr-pimd.8
+build/doc/manpages/_build/man/frr-ripd.8
+build/doc/manpages/_build/man/frr-ripngd.8
+build/doc/manpages/_build/man/frr-watchfrr.8
+build/doc/manpages/_build/man/frr-zebra.8
+build/doc/manpages/_build/man/frr.1
+build/doc/manpages/_build/man/mtracebis.8
+build/doc/manpages/_build/man/vtysh.1

debian/rules

@@ -32,7 +32,7 @@ endif
 export PYTHON=python3
 
 %:
-	dh $@ --with=$(DH_WITH_SYSTEMD)autoreconf --parallel
+	dh $@ -Bbuild --with=$(DH_WITH_SYSTEMD)autoreconf --parallel
 
 override_dh_auto_configure:
 	$(shell dpkg-buildflags --export=sh); \
@@ -77,7 +77,7 @@ override_dh_auto_install:
 ifeq ($(filter pkg.frr.nosystemd,$(DEB_BUILD_PROFILES)),)
 	cp tools/frr.service debian/frr.service
 endif
-	cp tools/frrinit.sh debian/frr.init
+	cp build/tools/frrinit.sh debian/frr.init
 	-rm -f debian/tmp/usr/lib/frr/frr
 
 # install config files
@@ -113,6 +113,11 @@ override_dh_makeshlibs:
 override_dh_missing:
 	dh_missing --fail-missing
 
+ifneq ($(filter nocheck,$(DEB_BUILD_PROFILES) $(DEB_BUILD_OPTIONS)),)
+override_dh_auto_test:
+	true
+endif
+
 override_dh_auto_clean:
 # we generally do NOT want a full distclean since that wipes both
 # debian/changelog and config.version