First batch of obvious changes - use better shellism, only call make (without make install).

live-build/auto/build

@@ -32,10 +32,7 @@ if [ "${IMAGEFORMAT:-}" = "ubuntu-image" ]; then
 		mv seed.manifest "$PREFIX".manifest
 	else
 		# First we need to build the gadget tree
-		(
-			cd config/$PREFIX-gadget
-			make &&	make install
-		)
+		make -C "config/$PREFIX-gadget"
 		ubuntu-image classic $UBUNTU_IMAGE_ARGS \
 			-p $PROJECT -a $ARCH --subarch $SUBARCH \
 			-o "$PREFIX".img config/$PREFIX-gadget/install

live-build/auto/config

@@ -218,12 +218,8 @@ case $IMAGEFORMAT in
 			# classic images
 
 			UBUNTU_IMAGE_ARGS=""
-			if [ "$PROPOSED" ]; then
-				UBUNTU_IMAGE_ARGS="$UBUNTU_IMAGE_ARGS --with-proposed"
-			fi
-			if [ "$EXTRA_PPAS" ]; then
-				UBUNTU_IMAGE_ARGS="$UBUNTU_IMAGE_ARGS --extra-ppas \"$EXTRA_PPAS\""
-			fi
+			UBUNTU_IMAGE_ARGS="$UBUNTU_IMAGE_ARGS${PROPOSED:+ --with-proposed}"
+			UBUNTU_IMAGE_ARGS="$UBUNTU_IMAGE_ARGS${EXTRA_PPAS:+ --extra-ppas \"$EXTRA_PPAS\"}"
 
 			git clone lp:~canonical-foundations/snap-$MODEL/+git/github-mirror -b classic config/$PREFIX-gadget