Bugfix: work on multi-arch enabled build systems

debian/changelog

@@ -3,6 +3,8 @@ debian-cd (3.1.15) UNRELEASED; urgency=low
   [ Steve McIntyre ]
   * Add "UEFI" text to the UEFI installer menu title to make it easier for
     end users to distinguish between UEFI and BIOS boot.
+  * tools/apt-selection: pass APT::Architectures:: when calling apt;
+    otherwise if we're running on a multi-arch system apt will break
 
   [ Samuel Thibault ]
   * Make kfreebsd & hurd images usbkey-bootable. Closes: #739422

tools/apt-selection

@@ -34,6 +34,7 @@ options=" -q -o Dir::State::status=$APTTMP/$CODENAME-$ARCH/status \
 		  -o APT::Cache::AllVersions=0 \
 		  -o APT::Cache::ShowVersion=1 \
 		  -o APT::Architecture=$ARCH \
+		  -o APT::Architectures::=$ARCH \ 
 		  -o Acquire::Languages=none"
 
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