abuild: fail fetch on http 404 errors

curl does not fail by default. it downloads the 404 error page instead
so we need add -f option to curl.

abuild.in

@@ -242,6 +242,7 @@ wget_fallback() {
 	while getopts "C:Lko:s" opt; do
 		case $opt in
 		'L') ;; # --location. wget does this by default
+		'f') ;; # --fail. wget does this by default
 		'C') wget_opts="$wget_opts -c";; # --continue-at
 		's') wget_opts="$wget_opts -q";; # --silent
 		'o') wget_opts="$wget_opts -O $OPTARG";; # --output
@@ -283,7 +284,7 @@ uri_fetch() {
 		fetcher=wget_fallback
 	else
 		fetcher=curl
-		opts="$opts -L"
+		opts="$opts -L -f"
 	fi
 
 	$fetcher $opts -o "$SRCDEST/$d.part" "$uri" \