abuild: implement sourcecheck

This subcommand verifies if upstream sources still exists and echoes
an error if it does not.

This is supposed to be used from a script that checks the validity
of source regularily.

abuild.in

@@ -170,6 +170,16 @@ md5check() {
 	cd "$srcdir" && echo "$md5sums" | md5sum -c 
 }
 
+# verify upstream sources
+sourcecheck() {
+	local s
+	for s in $source; do
+		if is_remote $s; then
+			wget -q -s $s || return 1
+		fi
+	done
+}
+	
 uri_fetch() {
 	local uri="$1"
 	local d="${uri##*/}"	# $(basename $uri)
@@ -1182,6 +1192,7 @@ usage() {
 	echo "  cleanpkg    Remove already built binary and source package"
 	echo "  cleancache  Remove downloaded files from \$SRCDEST"
 	echo "  srcpkg      Make a source package"
+	echo "  sourcecheck Check if remote source package exists upstream"
 	echo "  up2date     Compare target and sources dates"
 	echo "  installdeps Install packages listed in makedepends and depends"
 	echo "  uninstalldeps Uninstall packages listed in makedepends and depends"