debian/: finish Multi-Arch support and migrate from /lib to /usr/lib

This commit does two interleaved things:

* finis Multi-Arch support by changing dirs names, missing in commit:
   637406a0

 ("iptables: make it Multi-Arch: foreign")

* move libs from /lib to /usr/lib/

Therefore, the final change is, for example:
 /lib -> /usr/lib/x86_64-linux-gnu

Files already under /usr/lib are simply moved to /usr/lib/<arch>
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>

debian/iptables-dev.install

 include/linux/netfilter_ipv4/ip_queue.h usr/include/linux/netfilter_ipv4/
-lib/lib*.so
-lib/pkgconfig usr/lib
+usr/lib/*/lib*.so
+usr/lib/*/pkgconfig
 usr/include

debian/iptables-nftables-compat.install

-lib/xtables/libarpt_*.so
-lib/xtables/libebt_*.so
+usr/lib/*/xtables/libarpt_*.so
+usr/lib/*/xtables/libebt_*.so
 usr/sbin/*-compat*		sbin
 usr/sbin/xtables-compat-multi	sbin

debian/iptables.install

 iptables/iptables-apply usr/sbin
 iptables/iptables.xslt usr/share/iptables
-lib/libip*.so.*
-lib/xtables/libip*.so
-lib/xtables/libxt_*.so
+usr/lib/*/libip*.so.*
+usr/lib/*/xtables/libip*.so
+usr/lib/*/xtables/libxt_*.so
 usr/sbin/ip6tables sbin
 usr/sbin/ip6tables-restore sbin
 usr/sbin/ip6tables-save sbin

debian/libxtables11.install

-lib/libxtables*.so.*
+usr/lib/*/libxtables*.so.*

debian/rules

@@ -2,17 +2,21 @@
 
 export V=1
 
+DEB_HOST_MULTIARCH ?= $(shell dpkg-architecture -qDEB_HOST_MULTIARCH)
+LIB_DIR := /usr/lib/$(DEB_HOST_MULTIARCH)
+
 _dhopts := --with autoreconf
 
 _shlibdeps := \
-  -a -Xlib/xtables \
+  -a -X$(LIB_DIR) \
   -l$(CURDIR)/debian/build/extensions/.libs
 
 _configure := \
   --disable-libipq \
   --enable-devel \
-  --libdir=/lib \
-  --with-xtlibdir=/lib/xtables
+  --libdir=$(LIB_DIR) \
+  --with-xtlibdir=$(LIB_DIR)/xtables
+
 
 %:
 	dh $@ $(_dhopts)