add download of the tar.gz from tag to build file of Xtrapol8

Xtrapol8/build

@@ -10,8 +10,12 @@ pbuild::compile() {
     :
 }
 pbuild::install(){
+    # modbuild does not fetch config.yaml urls, so download here;
+    # rm the tarball afterwards so it does not ship inside the module
     mkdir "$PREFIX/bin"
-    cd "$PREFIX/bin" 
-    tar -xf "${BUILDBLOCK_DIR}/Xtrapol8-${V_PKG}.tar.gz" --strip-components=1
+    cd "$PREFIX/bin"
+    wget -O "Xtrapol8-${V_PKG}.tar.gz" "https://github.com/ElkeDeZitter/Xtrapol8/archive/refs/tags/v.${V_PKG}.tar.gz"
+    tar -xf "Xtrapol8-${V_PKG}.tar.gz" --strip-components=1
+    rm "Xtrapol8-${V_PKG}.tar.gz"
 }