builddeb: rework how output dir and platform are specified

This makes it possible to write tests for both builddeb and dockerdeb
that actually build .debs and then sanity check the contents.

Makefile

@@ -159,9 +159,7 b' osx:'
 
 deb:
 	mkdir -p packages/debian-unknown
-	contrib/builddeb
-	mv debbuild/*.deb packages/debian-unknown
-	rm -rf debbuild
+	contrib/builddeb --release unknown
 
 docker-debian-jessie:
 	mkdir -p packages/debian-jessie

contrib/builddeb

@@ -7,9 +7,14 b''
 . $(dirname $0)/packagelib.sh
 
 BUILD=1
-DEBBUILDDIR="$PWD/debbuild"
+DEBVERSION=jessie
 while [ "$1" ]; do
     case "$1" in
+    --release )
+        shift
+        DEBVERSION="$1"
+        shift
+        ;;
     --prepare )
         shift
         BUILD=
@@ -26,6 +31,8 b' while [ "$1" ]; do'
     esac
 done
 
+DEBBUILDDIR=${OUTPUTDIR:="$PWD/debbuild"}
+
 set -u
 
 rm -rf $DEBBUILDDIR

contrib/dockerdeb

@@ -8,13 +8,14 b' export ROOTDIR=$(cd $BUILDDIR/..; pwd)'
 
 checkdocker
 
+DEBPLATFORM="$1"
 PLATFORM="debian-$1"
 shift # extra params are passed to build process
 
 initcontainer $PLATFORM
 
-DEBBUILDDIR=$ROOTDIR/packages/$PLATFORM
-contrib/builddeb --debbuilddir $DEBBUILDDIR/staged --prepare
+DEBBUILDDIR=${OUTPUTDIR:=$ROOTDIR/packages/$PLATFORM}
+OUTPUTDIR=$DEBBUILDDIR/staged contrib/builddeb --release $DEBPLATFORM --prepare
 
 DSHARED=/mnt/shared/
 if [ $(uname) = "Darwin" ] ; then