snapcraft: Add libyang to snap package

Signed-off-by: Martin Winter <mwinter@opensourcerouting.org>

snapcraft/snapcraft.yaml.in

@@ -238,8 +238,24 @@ parts:
         plugin: cmake
         configflags:
            - -DCMAKE_BUILD_TYPE=Release
+    libyang:
+        build-packages:
+           - cmake
+           - make
+           - gcc
+           - libpcre3-dev
+        stage-packages:
+           - libpcre3
+        source: https://github.com/CESNET/libyang.git
+        source-type: git
+        source-tag: v0.16-r3
+        plugin: cmake
+        configflags:
+           - -DCMAKE_INSTALL_PREFIX:PATH=/usr
+           - -DENABLE_LYD_PRIV=ON
+           - -DCMAKE_BUILD_TYPE:String="Release"
     frr: 
-        after: [rtrlib]
+        after: [rtrlib,libyang]
         build-packages:
            - gcc
            - autoconf
@@ -344,3 +360,8 @@ parts:
             README.snap_build.md: doc/README.snap_build.md
             extra_version_info.txt: doc/extra_version_info.txt
 
+passthrough:
+    layout:
+         /usr/lib/x86_64-linux-gnu/libyang:
+             bind: $SNAP/usr/lib/x86_64-linux-gnu/libyang
+