Setup snap portable builds

snap/snapcraft.yaml

@@ -172,6 +172,12 @@ parts:
     override-build: |
       snapcraftctl set-version $(cat VERSION)
 
+      # Portable build
+      test -f /usr/bin/gcc_real || mv -v /usr/bin/gcc /usr/bin/gcc_real
+      test -f /usr/bin/gcc || cp -v ./docker/gcc /usr/bin/gcc
+      test -f /usr/bin/g++_real || mv -v /usr/bin/g++ /usr/bin/g++_real
+      test -f /usr/bin/g++ || cp -v ./docker/g++ /usr/bin/g++
+
       pip3 install --user -r requirements.txt
 
       # Build the SuperBuild libraries