snapcraft.yaml: include additional dependencies

When building classic images, ubuntu-image will optionally run make to
build the gadget tree. Canonical's gadget snaps use a Makefile to create
certain artifacts, and some important commands used in this Makefile
(chdist, grub-mkimage) are provided by devscripts and grub-common. Add
these dependencies as stage-packages so that ubuntu-image can readily
build some gadget snaps, especially on non-Ubuntu systems.

Signed-off-by: Dilyn Corner <[email protected]>

snapcraft.yaml

@@ -17,7 +17,7 @@ environment:
   GCONV_PATH: /snap/core20/current/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/gconv
   PYTHONPATH: $SNAP/usr/lib/python3/dist-packages:$PYTHONPATH
   DEBOOTSTRAP_DIR: $SNAP/usr/share/debootstrap
-
+  PERL5LIB: $SNAP/usr/share/perl5:$SNAP/usr/share/perl:$PERL5LIB
 
 apps:
   ubuntu-image:
@@ -45,6 +45,8 @@ parts:
       - make
       - kpartx
       - qemu-utils
+      - devscripts
+      - grub-common
     build-attributes: [ enable-patchelf ]
     override-build: |
       ins_bin=$SNAPCRAFT_PART_INSTALL/bin/