--- a/run	Tue Aug 25 15:55:09 2015 +0200
+++ b/run	Tue Aug 25 15:55:16 2015 +0200
@@ -2,7 +2,12 @@
 
 export LC_ALL=C
 
-platforms=${1-$(find platforms -mindepth 1 -maxdepth 1 -type d)}
+if test "$@"; then
+    platforms="$1"
+    shift
+else
+    platforms=$(find platforms -mindepth 1 -maxdepth 1 -type d)
+fi
 
 for platform in $platforms; do
     system=$(basename $platform)