Retry curl requests in fetch_libs.sh

util/fetch_libs.sh

@@ -8,6 +8,8 @@ fi
 
 DEST="$1"
 
+CURL="curl -sSL --retry 20 --retry-connrefused"
+
 rm -rf "$DEST"
 mkdir -p "$DEST"
 
@@ -47,7 +49,7 @@ do
 		"CleanDistribution")
 			if [[ "$platform" == windows* ]]; then
 				URL="https://ftp.cs.ru.nl/Clean/builds/$platform/clean-$distribution-$platform-latest.zip"
-				curl -sSL "$URL" -o temp.zip
+				$CURL "$URL" -o temp.zip
 				unzip -q -d "$DEST" temp.zip "clean-$distribution/Libraries/*"
 				rm temp.zip
 				mv "$DEST/clean-$distribution/Libraries"/* "$DEST"
@@ -56,7 +58,7 @@ do
 			else
 				URL="https://ftp.cs.ru.nl/Clean/builds/$platform/clean-$distribution-$platform-latest.tgz"
 				echo "Fetching $URL..."
-				curl -sSL "$URL" | tar xz --exclude=exe -C "$DEST" --strip-components=2 "clean-$distribution/lib"
+				$CURL "$URL" | tar xz --exclude=exe -C "$DEST" --strip-components=2 "clean-$distribution/lib"
 			fi
 			;;
 		*)