Try explicitly setting excludes to an array

Otherwise, if it is unset, it appears that (at least on macos), the following
expands to an empty string argument rather than no arguments:

    "${excludes[@]}"

makem.sh

@@ -407,7 +407,7 @@ function files-project {
   set -x
     [[ $1 ]] && pattern="/$1" || pattern="."
 
-    local excludes
+    local excludes=()
     for submodule in $(submodules)
     do
         excludes+=(":!:$submodule")