Enable core18 builds

debian/changelog

@@ -1,3 +1,11 @@
+livecd-rootfs (2.525.35) UNRELEASED; urgency=medium
+
+  * Did not expect the bionic branch being so outdated. Backport support
+    for fetching core18 model assertions on bionic hosts. This enables build
+    support for ubuntu-core 18 images. (LP: #1852332)
+
+ -- Łukasz 'sil2100' Zemczak <lukasz.zemczak@ubuntu.com>  Tue, 12 Nov 2019 21:05:29 +0100
+
 livecd-rootfs (2.525.34) bionic; urgency=medium
 
   * Add support for HyperV Gallery Images (LP: #1837088)

live-build/auto/config

@@ -205,6 +205,14 @@ case $IMAGEFORMAT in
 					&& UBUNTU_IMAGE_ARGS="--image-size 3700M"
 					;;
 			esac
+			case $SUITE in
+				xenial)
+					# Ubuntu Core 16
+					;;
+				*)
+					# Ubuntu Core 18
+					MODEL="ubuntu-core-18-${MODEL#pc-}" ;;
+			esac
 
 			case "$ARCH+${SUBARCH:-}" in
 				amd64+kassel)