Fix portability issues discovered with fresh snap install.

ARCH=native fixes SIGILL issues on other amd64 processors.
Static library dependencies where supported.
Package libunbound2 in the snap.

contrib/snap/daemon.bash

@@ -1,5 +1,6 @@
 #!/bin/bash -e
 
+export LD_LIBRARY_PATH=${SNAP_LIBRARY_PATH}:${SNAP}/usr/lib/x86_64-linux-gnu
 export HOME=${SNAP_DATA}
 cd ${SNAP_DATA}
 

contrib/snap/wallet.bash

@@ -1,5 +1,6 @@
 #!/bin/bash -e
 
+export LD_LIBRARY_PATH=${SNAP_LIBRARY_PATH}:${SNAP}/usr/lib/x86_64-linux-gnu
 export HOME=${SNAP_USER_DATA}
 cd ${SNAP_USER_DATA}
 

snapcraft.yaml

@@ -42,6 +42,12 @@ parts:
 
     cmake-build:
         plugin: cmake
+        configflags:
+            - -DBDB_STATIC=1
+            - -DUPNP_STATIC=1
+            - -DBoost_USE_STATIC_LIBS=1
+            - -DBoost_USE_STATIC_RUNTIME=1
+            - -DARCH=default
         source: .
         build-packages:
             - gcc
@@ -58,5 +64,8 @@ parts:
             - bison
             - doxygen
             - graphviz
+        stage-packages:
+            - libunbound2
         snap:
             - bin
+            - usr