Run apt update before build

installJRMC

@@ -1120,8 +1120,12 @@ install_mc_snap() {
 		      - make
 		      - libglib2.0-dev
 		      - git
+		      - pkg-config
 		    stage-packages:
 		      - libgtk-3-0
+		    override-build: |
+		      apt-get update
+		      snapcraftctl build
 
 		apps:
 		  mediacenter: